[Code of Federal Regulations]
[Title 40, Volume 21]
[Revised as of July 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR141.32]

[Page 395-416]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 141_NATIONAL PRIMARY DRINKING WATER REGULATIONS--Table of Contents
 
                  Subpart D_Reporting and Recordkeeping
 
Sec. 141.32  Public notification.

    The requirements in this section apply until the requirements of 
Subpart Q of this part are applicable. Public water systems where EPA 
directly implements the public water system supervision program must 
comply with the requirements in Subpart Q of this part on October 31, 
2000. All other public water systems must comply with the requirements 
in Subpart Q of this part on May 6, 2002 or on the date the State-
adopted rule becomes effective, whichever comes first.
    (a) Maximum contaminant levels (MCLs), maximum residual disinfectant 
levels (MRDLs). The owner or operator of a public water system which 
fails to comply with an applicable MCL or treatment technique 
established by this part or which fails to comply with the requirements 
of any schedule prescribed pursuant to a variance or exemption, shall 
notify persons served by the system as follows:
    (1) Except as provided in paragraph (a)(3) of this section, the 
owner or operator of a public water system must give notice:
    (i) By publication in a daily newspaper of general circulation in 
the area served by the system as soon as possible, but in no case later 
than 14 days after the violation or failure. If the area served by a 
public water system is not served by a daily newspaper of general 
circulation, notice shall instead be given by publication in a weekly 
newspaper of general circulation serving the area; and
    (ii) By mail delivery (by direct mail or with the water bill), or by 
hand delivery, not later than 45 days after the violation or failure. 
The State may waive mail or hand delivery if it determines that the 
owner or operator of the public water system in violation has corrected 
the violation or failure within the 45-day period. The State must make 
the waiver in writing and within the 45-day period; and
    (iii) For violations of the MCLs of contaminants or MRDLs of 
disinfectants that may pose an acute risk to human health, by furnishing 
a copy of the notice to the radio and television stations serving the 
area served by the public water system as soon as possible but in no 
case later than 72 hours after the violation. The following violations 
are acute violations:
    (A) Any violations specified by the State as posing an acute risk to 
human health.
    (B) Violation of the MCL for nitrate or nitrite as defined in Sec. 
141.62 and determined according to Sec. 141.23(i)(3).
    (C) Violation of the MCL for total coliforms, when fecal coliforms 
or E. coli are present in the water distribution system, as specified in 
Sec. 141.63(b).
    (D) Occurrence of a waterborne disease outbreak, as defined in Sec. 
141.2, in an unfiltered system subject to the requirements of subpart H 
of this part, after December 30, 1991 (see Sec. 141.71(b)(4)).
    (E) Violation of the MRDL for chlorine dioxide as defined in Sec. 
141.65 and determined according to Sec. 141.133(c)(2).
    (2) Except as provided in paragraph (a)(3) of this section, 
following the initial notice given under paragraph (a)(1) of this 
section, the owner or operator of the public water system must give 
notice at least once every three months by mail delivery (by direct mail 
or with the water bill) or by hand delivery, for as long as the 
violation or failure exists.
    (3)(i) In lieu of the requirements of paragraphs (a) (1) and (2) of 
this section, the owner or operator of a community water system in an 
area that is not served by a daily or weekly newspaper of general 
circulation must give notice by hand delivery or by continuous posting 
in conspicuous places within the area served by the system. Notice by 
hand delivery or posting must begin as soon as possible, but no later 
than 72 hours after the violation or failure for acute violations (as 
defined in paragraph (a)(1)(iii) of this section), or 14 days after the 
violation or failure (for any other violation). Posting must continue 
for as long as the

[[Page 396]]

violation or failure exists. Notice by hand delivery must be repeated at 
least every three months for as long as the violation or failure exists.
    (ii) In lieu of the requirements of paragraphs (a) (1) and (2) of 
this section, the owner or operator of a non-community water system may 
give notice by hand delivery or by continuous posting in conspicuous 
places within the area served by the system. Notice by hand delivery or 
posting must begin as soon as possible, but no later than 72 hours after 
the violation or failure for acute violations (as defined in paragraph 
(a)(1)(iii) of this section), or 14 days after the violation or failure 
(for any other violation). Posting must continue for as long as the 
violation or failure exists. Notice by hand delivery must be repeated at 
least every three months for as long as the violation or failure exists.
    (b) Other violations, variances, exemptions. The owner or operator 
of a public water system which fails to perform monitoring required by 
section 1445(a) of the Act (including monitoring required by the 
National Primary Drinking Water Regulations (NPDWRs) of this part), 
fails to comply with a testing procedure established by this part, is 
subject to a variance granted under section 1415(a)(1)(A) or 1415(a)(2) 
of the Act, or is subject to an exemption under section 1416 of the Act, 
shall notify persons served by the system as follows:
    (1) Except as provided in paragraph (b)(3) or (b)(4) of this 
section, the owner or operator of a public water system must give notice 
within three months of the violation or granting of a variance or 
exemption by publication in a daily newspaper of general circulation in 
the area served by the system. If the area served by a public water 
system is not served by a daily newspaper of general circulation, notice 
shall instead be given by publication in a weekly newspaper of general 
circulation serving the area.
    (2) Except as provided in paragraph (b)(3) or (b)(4) of this 
section, following the initial notice given under paragraph (b)(1) of 
this section, the owner or operator of the public water system must give 
notice at least once every three months by mail delivery (by direct mail 
or with the water bill) or by hand delivery, for as long as the 
violation exists. Repeat notice of the existence of a variance or 
exemption must be given every three months for as long as the variance 
or exemption remains in effect.
    (3)(i) In lieu of the requirements of paragraphs (b)(1) and (b)(2) 
of this section, the owner or operator of a community water system in an 
area that is not served by a daily or weekly newspaper of general 
circulation must give notice, within three months of the violation or 
granting of the variance or exemption, by hand delivery or by continuous 
posting in conspicuous places with the area served by the system. 
Posting must continue for as long as the violation exists or a variance 
or exemption remains in effect. Notice by hand delivery must be repeated 
at least every three months for as long as the violation exists or a 
variance or exemption remains in effect.
    (ii) In lieu of the requirements of paragraphs (b)(1) and (b)(2) of 
this section, the owner or operator of a non-community water system may 
give notice, within three months of the violation or the granting of the 
variance or exemption, by hand delivery or by continuous posting in 
conspicuous places within the area served by the system. Posting must 
continue for as long as the violation exists, or a variance or exemption 
remains in effect. Notice by hand delivery must be repeated at least 
every three months for as long as the violation exists or a variance or 
exemption remains in effect.
    (4) In lieu of the requirements of paragraphs (b)(1), (b)(2), and 
(b)(3) of this section, the owner or operator of a public water system, 
at the discretion of the State, may provide less frequent notice for 
minor monitoring violations as defined by the State, if EPA has approved 
the State's application for a program revision under Sec. 142.16. 
Notice of such violations must be given no less frequently than 
annually.
    (c) Notice to new billing units. The owner or operator of a 
community water system must give a copy of the most recent public notice 
for any outstanding violation of any maximum contaminant level, or any 
maximum residual disinfectant level, or any

[[Page 397]]

treatment technique requirement, or any variance or exemption schedule 
to all new billing units or new hookups prior to or at the time service 
begins.
    (d) General content of public notice. Each notice required by this 
section must provide a clear and readily understandable explanation of 
the violation, any potential adverse health effects, the population at 
risk, the steps that the public water system is taking to correct such 
violation, the necessity for seeking alternative water supplies, if any, 
and any preventive measures the consumer should take until the violation 
is corrected. Each notice shall be conspicuous and shall not contain 
unduly technical language, unduly small print, or similar problems that 
frustrate the purpose of the notice. Each notice shall include the 
telephone number of the owner, operator, or designee of the public water 
system as a source of additional information concerning the notice. 
Where appropriate, the notice shall be multi-lingual.
    (e) Mandatory health effects language. When providing the 
information on potential adverse health effects required by paragraph 
(d) of this section in notices of violations of maximum contaminant 
levels or treatment technique requirements, or notices of the granting 
or the continued existence of exemptions or variances, or notices of 
failure to comply with a variance or exemption schedule, the owner or 
operator of a public water system shall include the language specified 
below for each contaminant. (If language for a particular contaminant is 
not specified below at the time notice is required, this paragraph does 
not apply.)
    (1) Trichloroethylene. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that 
trichloroethylene is a health concern at certain levels of exposure. 
This chemical is a common metal cleaning and dry cleaning fluid. It 
generally gets into drinking water by improper waste disposal. This 
chemical has been shown to cause cancer in laboratory animals such as 
rats and mice when the animals are exposed at high levels over their 
lifetimes. Chemicals that cause cancer in laboratory animals also may 
increase the risk of cancer in humans who are exposed at lower levels 
over long periods of time. EPA has set forth the enforceable drinking 
water standard for trichloroethylene at 0.005 parts per million (ppm) to 
reduce the risk of cancer or other adverse health effects which have 
been observed in laboratory animals. Drinking water which meets this 
standard is associated with little to none of this risk and should be 
considered safe.
    (2) Carbon tetrachloride. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that 
carbon tetrachloride is a health concern at certain levels of exposure. 
This chemical was once a popular household cleaning fluid. It generally 
gets into drinking water by improper waste disposal. This chemical has 
been shown to cause cancer in laboratory animals such as rats and mice 
when the animals are exposed at high levels over their lifetimes. 
Chemicals that cause cancer in laboratory animals also may increase the 
risk of cancer in humans who are exposed at lower levels over long 
periods of of time. EPA has set the enforceable drinking water standard 
for carbon tetrachloride at 0.005 parts per million (ppm) to reduce the 
risk of cancer or other adverse health effects which have been observed 
in laboratory animals. Drinking water which meets this standard is 
associated with little to none of this risk and should be considered 
safe.
    (3) 1,2-Dichloroethane. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that 1,2-
dichloroethane is a health concern at certain levels of exposure. This 
chemical is used as a cleaning fluid for fats, oils, waxes, and resins. 
It generally gets into drinking water from improper waste disposal. This 
chemical has been shown to cause cancer in laboratory animals such as 
rats and mice when the animals are exposed at high levels over their 
lifetimes. Chemicals that cause cancer in laboratory animals also may 
increase the risk of cancer in humans who are exposed at lower levels 
over long periods of time. EPA has set the enforceable drinking water 
standard for 1,2-dichloroethane at 0.005 parts per million (ppm) to 
reduce the

[[Page 398]]

risk of cancer or other adverse health effects which have been observed 
in laboratory animals. Drinking water which meets this standard is 
associated with little to none of this risk and should be considered 
safe.
    (4) Vinyl chloride. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that vinyl 
chloride is a health concern at certain levels of exposure. This 
chemical is used in industry and is found in drinking water as a result 
of the breakdown of related solvents. The solvents are used as cleaners 
and degreasers of metals and generally get into drinking water by 
improper waste disposal. This chemical has been associated with 
significantly increased risks of cancer among certain industrial workers 
who were exposed to relatively large amounts of this chemical during 
their working careers. This chemical has also been shown to cause cancer 
in laboratory animals when the animals are exposed at high levels over 
their lifetimes. Chemicals that cause increased risk of cancer among 
exposed industrial workers and in laboratory animals also may increase 
the risk of cancer in humans who are exposed at lower levels over long 
periods of time. EPA has set the enforceable drinking water standard for 
vinyl chloride at 0.002 part per million (ppm) to reduce the risk of 
cancer or other adverse health effects which have been observed in 
humans and laboratory animals. Drinking water which meets this standard 
is associated with little to none of this risk and should be considered 
safe.
    (5) Benzene. The United States Environmental Protection Agency (EPA) 
sets drinking water standards and has determined that benzene is a 
health concern at certain levels of exposure. This chemical is used as a 
solvent and degreaser of metals. It is also a major component of 
gasoline. Drinking water contamination generally results from leaking 
undergound gasoline and petroleum tanks or improper waste disposal. This 
chemical has been associated with significantly increased risks of 
leukemia among certain industrial workers who were exposed to relatively 
large amounts of this chemical during their working careers. This 
chemical has also been shown to cause cancer in laboratory animals when 
the animals are exposed at high levels over their lifetimes. Chemicals 
that cause increased risk of cancer among exposed industrial workers and 
in laboratory animals also may increase the risk of cancer in humans who 
are exposed at lower levels over long periods of time. EPA has set the 
enforceable drinking water standard for benzene at 0.005 parts per 
million (ppm) to reduce the risk of cancer or other adverse health 
effects which have been observed in humans and laboratory animals. 
Drinking water which meets this standard is associated with little to 
none of this risk and should be considered safe.
    (6) 1,1-Dichloroethylene. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that 1,1-
dichloroethylene is a health concern at certain levels of exposure. This 
chemical is used in industry and is found in drinking water as a result 
of the breakdown of related solvents. The solvents are used as cleaners 
and degreasers of metals and generally get into drinking water by 
improper waste disposal. This chemical has been shown to cause liver and 
kidney damage in laboratory animals such as rats and mice when the 
animals are exposed at high levels over their lifetimes. Chemicals which 
cause adverse effects in laboratory animals also may cause adverse 
health effects in humans who are exposed at lower levels over long 
periods of time. EPA has set the enforceable drinking water standard for 
1,1-dichloroethylene at 0.007 parts per million (ppm) to reduce the risk 
of these adverse health effects which have been observed in laboratory 
animals. Drinking water which meets this standard is associated with 
little to none of this risk and should be considered safe.
    (7) Para-dichlorobenzene. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that para-
dichlorobenzene is a health concern at certain levels of exposure. This 
chemical is a component of deodorizers, moth balls, and pesticides. It 
generally gets into drinking water by improper waste disposal. This 
chemical

[[Page 399]]

has been shown to cause liver and kidney damage in laboratory animals 
such as rats and mice when the animals are exposed to high levels over 
their lifetimes. Chemicals which cause adverse effects in laboratory 
animals also may cause adverse health effects in humans who are exposed 
at lower levels over long periods of time. EPA has set the enforceable 
drinking water standard for para-dichlorobenzene at 0.075 parts per 
million (ppm) to reduce the risk of these adverse health effects which 
have been observed in laboratory animals. Drinking water which meets 
this standard is associated with little to none of this risk and should 
be considered safe.
    (8) 1,1,1-Trichloroethane. The United States Environmental 
Protection Agency (EPA) sets drinking water standards and has determined 
that the 1,1,1-trichloroethane is a health concern at certain levels of 
exposure. This chemical is used as a cleaner and degreaser of metals. It 
generally gets into drinking water by improper waste disposal. This 
chemical has been shown to damage the liver, nervous system, and 
circulatory system of laboratory animals such as rats and mice when the 
animals are exposed at high levels over their lifetimes. Some industrial 
workers who were exposed to relatively large amounts of this chemical 
during their working careers also suffered damage to the liver, nervous 
system, and circulatory system. Chemicals which cause adverse effects 
among exposed industrial workers and in laboratory animals also may 
cause adverse health effects in humans who are exposed at lower levels 
over long periods of time. EPA has set the enforceable drinking water 
standard for 1,1,1-trichloroethane at 0.2 parts per million (ppm) to 
protect against the risk of these adverse health effects which have been 
observed in humans and laboratory animals. Drinking water which meets 
this standard is associated with little to none of this risk and should 
be considered safe.
    (9) Fluoride.
    [Note: EPA is not specifying language that must be included in a 
public notice for a violation of the fluoride maximum contaminant level 
in this section because Sec. 143.5 of this part includes the necessary 
information. See paragraph (f) of this section.]
    (10) Microbiological contaminants (for use when there is a violation 
of the treatment technique requirements for filtration and disinfection 
in subpart H or subpart P of this part). The United States Environmental 
Protection Agency (EPA) sets drinking water standards and has determined 
that the presence of microbiological contaminants are a health concern 
at certain levels of exposure. If water is inadequately treated, 
microbiological contaminants in that water may cause disease. Disease 
symptoms may include diarrhea, cramps, nausea, and possibly jaundice, 
and any associated headaches and fatigue. These symptoms, however, are 
not just associated with disease-causing organisms in drinking water, 
but also may be caused by a number of factors other than your drinking 
water. EPA has set enforceable requirements for treating drinking water 
to reduce the risk of these adverse health effects. Treatment such as 
filtering and disinfecting the water removes or destroys microbiological 
contaminants. Drinking water which is treated to meet EPA requirements 
is associated with little to none of this risk and should be considered 
safe.
    (11) Total coliforms (To be used when there is a violation of Sec. 
141.63(a), and not a violation of Sec. 141.63(b)). The United States 
Environmental Protection Agency (EPA) sets drinking water standards and 
has determined that the presence of total coliforms is a possible health 
concern. Total coliforms are common in the environment and are generally 
not harmful themselves. The presence of these bacteria in drinking 
water, however, generally is a result of a problem with water treatment 
or the pipes which distribute the water, and indicates that the water 
may be contaminated with organisms that can cause disease. Disease 
symptoms may include diarrhea, cramps, nausea, and possibly jaundice, 
and any associated headaches and fatigue. These symptoms, however, are 
not just associated with disease-causing organisms in drinking water, 
but also may be caused by a number of factors other than your drinking 
water. EPA has set an enforceable drinking water standard for total 
coliforms to reduce the risk of these adverse health effects. Under this

[[Page 400]]

standard, no more than 5.0 percent of the samples collected during a 
month can contain these bacteria, except that systems collecting fewer 
than 40 samples/month that have one total coliform-positive sample per 
month are not violating the standard. Drinking water which meets this 
standard is usually not associated with a health risk from disease-
causing bacteria and should be considered safe.
    (12) Fecal Coliforms/E. coli (To be used when there is a violation 
of Sec. 141.63(b) or both Sec. 141.63 (a) and (b)). The United States 
Environmental Protection Agency (EPA) sets drinking water standards and 
has determined that the presence of fecal coliforms or E. coli is a 
serious health concern. Fecal coliforms and E. coli are generally not 
harmful themselves, but their presence in drinking water is serious 
because they usually are associated with sewage or animal wastes. The 
presence of these bacteria in drinking water is generally a result of a 
problem with water treatment or the pipes which distribute the water, 
and indicates that the water may be contaminated with organisms that can 
cause disease. Disease symptoms may include diarrhea, cramps, nausea, 
and possibly jaundice, and associated headaches and fatigue. These 
symptoms, however, are not just associated with disease-causing 
organisms in drinking water, but also may be caused by a number of 
factors other than your drinking water. EPA has set an enforceable 
drinking water standard for fecal coliforms and E. coli to reduce the 
risk of these adverse health effects. Under this standard all drinking 
water samples must be free of these bacteria. Drinking water which meets 
this standard is associated with little or none of this risk and should 
be considered safe. State and local health authorities recommend that 
consumers take the following precautions: [To be inserted by the public 
water system, according to instructions from State or local 
authorities].
    (13) Lead. The United States Environmental Protection Agency (EPA) 
sets drinking water standards and has determined that lead is a health 
concern at certain exposure levels. Materials that contain lead have 
frequently been used in the construction of water supply distribution 
systems, and plumbing systems in private homes and other buildings. The 
most commonly found materials include service lines, pipes, brass and 
bronze fixtures, and solders and fluxes. Lead in these materials can 
contaminate drinking water as a result of the corrosion that takes place 
when water comes into contact with those materials. Lead can cause a 
variety of adverse health effects in humans. At relatively low levels of 
exposure, these effects may include interference with red blood cell 
chemistry, delays in normal physical and mental development in babies 
and young children, slight deficits in the attention span, hearing, and 
learning abilities of children, and slight increases in the blood 
pressure of some adults. EPA's national primary drinking water 
regulation requires all public water systems to optimize corrosion 
control to minimize lead contamination resulting from the corrosion of 
plumbing materials. Public water systems serving 50,000 people or fewer 
that have lead concentrations below 15 parts per billion (ppb) in more 
than 90% of tap water samples (the EPA ``action level'') have optimized 
their corrosion control treatment. Any water system that exceeds the 
action level must also monitor their source water to determine whether 
treatment to remove lead in source water is needed. Any water system 
that continues to exceed the action level after installation of 
corrosion control and/or source water treatment must eventually replace 
all lead service lines contributing in excess of 15 (ppb) of lead to 
drinking water. Any water system that exceeds the action level must also 
undertake a public education program to inform consumers of ways they 
can reduce their exposure to potentially high levels of lead in drinking 
water.
    (14) Copper. The United States Environmental Protection Agency (EPA) 
sets drinking water standards and has determined that copper is a health 
concern at certain exposure levels. Copper, a reddish-brown metal, is 
often used to plumb residential and commercial structures that are 
connected to water distribution systems. Copper contaminating drinking 
water as a corrosion byproduct occurs as the result of the corrosion of 
copper pipes that remain

[[Page 401]]

in contact with water for a prolonged period of time. Copper is an 
essential nutrient, but at high doses it has been shown to cause stomach 
and intestinal distress, liver and kidney damage, and anemia. Persons 
with Wilson's disease may be at a higher risk of health effects due to 
copper than the general public. EPA's national primary drinking water 
regulation requires all public water systems to install optimal 
corrosion control to minimize copper contamination resulting from the 
corrosion of plumbing materials. Public water systems serving 50,000 
people or fewer that have copper concentrations below 1.3 parts per 
million (ppm) in more than 90% of tap water samples (the EPA ``action 
level'') are not required to install or improve their treatment. Any 
water system that exceeds the action level must also monitor their 
source water to determine whether treatment to remove copper in source 
water is needed.
    (15) Asbestos. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that asbestos 
fibers greater than 10 micrometers in length are a health concern at 
certain levels of exposure. Asbestos is a naturally occurring mineral. 
Most asbestos fibers in drinking water are less than 10 micrometers in 
length and occur in drinking water from natural sources and from 
corroded asbestos-cement pipes in the distribution system. The major 
uses of asbestos were in the production of cements, floor tiles, paper 
products, paint, and caulking; in transportation-related applications; 
and in the production of textiles and plastics. Asbestos was once a 
popular insulating and fire retardent material. Inhalation studies have 
shown that various forms of asbestos have produced lung tumors in 
laboratory animals. The available information on the risk of developing 
gastrointestinal tract cancer associated with the ingestion of asbestos 
from drinking water is limited. Ingestion of intermediate-range 
chrysotile asbestos fibers greater than 10 micrometers in length is 
associated with causing benign tumors in male rats. Chemicals that cause 
cancer in laboratory animals also may increase the risk of cancer in 
humans who are exposed over long periods of time. EPA has set the 
drinking water standard for asbestos at 7 million long fibers per liter 
to reduce the potential risk of cancer or other adverse health effects 
which have been observed in laboratory animals. Drinking water which 
meets the EPA standard is associated with little to none of this risk 
and should be considered safe with respect to asbestos.
    (16) Barium. The United States Environmental Protection Agency (EPA) 
sets drinking water standards and has determined that barium is a health 
concern at certain levels of exposure. This inorganic chemical occurs 
naturally in some aquifers that serve as sources of ground water. It is 
also used in oil and gas drilling muds, automotive paints, bricks, tiles 
and jet fuels. It generally gets into drinking water after dissolving 
from naturally occurring minerals in the ground. This chemical may 
damage the heart and cardiovascular system, and is associated with high 
blood pressure in laboratory animals such as rats exposed to high levels 
during their lifetimes. In humans, EPA believes that effects from barium 
on blood pressure should not occur below 2 parts per million (ppm) in 
drinking water. EPA has set the drinking water standard for barium at 2 
parts per million (ppm) to protect against the risk of these adverse 
health effects. Drinking water that meets the EPA standard is associated 
with little to none of this risk and is considered safe with respect to 
barium.
    (17) Cadmium. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that cadmium is a 
health concern at certain levels of exposure. Food and the smoking of 
tobacco are common sources of general exposure. This inorganic metal is 
a contaminant in the metals used to galvanize pipe. It generally gets 
into water by corrosion of galvanized pipes or by improper waste 
disposal. This chemical has been shown to damage the kidney in animals 
such as rats and mice when the animals are exposed at high levels over 
their lifetimes. Some industrial workers who were exposed to relatively 
large amounts of this chemical during working careers also suffered 
damage

[[Page 402]]

to the kidney. EPA has set the drinking water standard for cadmium at 
0.005 parts per million (ppm) to protect against the risk of these 
adverse health effects. Drinking water that meets the EPA standard is 
associated with little to none of this risk and is considered safe with 
respect to cadmium.
    (18) Chromium. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that chromium is 
a health concern at certain levels of exposure. This inorganic metal 
occurs naturally in the ground and is often used in the electroplating 
of metals. It generally gets into water from runoff from old mining 
operations and improper waste disposal from plating operations. This 
chemical has been shown to damage the kidney, nervous system, and the 
circulatory system of laboratory animals such as rats and mice when the 
animals are exposed at high levels. Some humans who were exposed to high 
levels of this chemical suffered liver and kidney damage, dermatitis and 
respiratory problems. EPA has set the drinking water standard for 
chromium at 0.1 parts per million (ppm) to protect against the risk of 
these adverse health effects. Drinking water that meets the EPA standard 
is associated with little to none of this risk and is considered safe 
with respect to chromium.
    (19) Mercury. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that mercury is a 
health concern at certain levels of exposure. This inorganic metal is 
used in electrical equipment and some water pumps. It usually gets into 
water as a result of improper waste disposal. This chemical has been 
shown to damage the kidney of laboratory animals such as rats when the 
animals are exposed at high levels over their lifetimes. EPA has set the 
drinking water standard for mercury at 0.002 parts per million (ppm) to 
protect against the risk of these adverse health effects. Drinking water 
that meets the EPA standard is associated with little to none of this 
risk and is considered safe with respect to mercury.
    (20) Nitrate. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that nitrate 
poses an acute health concern at certain levels of exposure. Nitrate is 
used in fertilizer and is found in sewage and wastes from human and/or 
farm animals and generally gets into drinking water from those 
activities. Excessive levels of nitrate in drinking water have caused 
serious illness and sometimes death in infants under six months of age. 
The serious illness in infants is caused because nitrate is converted to 
nitrite in the body. Nitrite interferes with the oxygen carrying 
capacity of the child's blood. This is an acute disease in that symptoms 
can develop rapidly in infants. In most cases, health deteriorates over 
a period of days. Symptoms include shortness of breath and blueness of 
the skin. Clearly, expert medical advice should be sought immediately if 
these symptoms occur. The purpose of this notice is to encourage parents 
and other responsible parties to provide infants with an alternate 
source of drinking water. Local and State health authorities are the 
best source for information concerning alternate sources of drinking 
water for infants. EPA has set the drinking water standard at 10 parts 
per million (ppm) for nitrate to protect against the risk of these 
adverse effects. EPA has also set a drinking water standard for nitrite 
at 1 ppm. To allow for the fact that the toxicity of nitrate and nitrite 
are additive, EPA has also established a standard for the sum of nitrate 
and nitrite at 10 ppm. Drinking water that meets the EPA standard is 
associated with little to none of this risk and is considered safe with 
respect to nitrate.
    (21) Nitrite. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that nitrite 
poses an acute health concern at certain levels of exposure. This 
inorganic chemical is used in fertilizers and is found in sewage and 
wastes from humans and/or farm animals and generally gets into drinking 
water as a result of those activities. While excessive levels of nitrite 
in drinking water have not been observed, other sources of nitrite have 
caused serious illness and sometimes death in infants under six months 
of age. The

[[Page 403]]

serious illness in infants is caused because nitrite interferes with the 
oxygen carrying capacity of the child's blood. This is an acute disease 
in that symptoms can develop rapidly. However, in most cases, health 
deteriorates over a period of days. Symptoms include shortness of breath 
and blueness of the skin. Clearly, expert medical advice should be 
sought immediately if these symptoms occur. The purpose of this notice 
is to encourage parents and other responsible parties to provide infants 
with an alternate source of drinking water. Local and State health 
authorities are the best source for information concerning alternate 
sources of drinking water for infants. EPA has set the drinking water 
standard at 1 part per million (ppm) for nitrite to protect against the 
risk of these adverse effects. EPA has also set a drinking water 
standard for nitrate (converted to nitrite in humans) at 10 ppm and for 
the sum of nitrate and nitrite at 10 ppm. Drinking water that meets the 
EPA standard is associated with little to none of this risk and is 
considered safe with respect to nitrite.
    (22) Selenium. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that selenium is 
a health concern at certain high levels of exposure. Selenium is also an 
essential nutrient at low levels of exposure. This inorganic chemical is 
found naturally in food and soils and is used in electronics, photocopy 
operations, the manufacture of glass, chemicals, drugs, and as a 
fungicide and a feed additive. In humans, exposure to high levels of 
selenium over a long period of time has resulted in a number of adverse 
health effects, including a loss of feeling and control in the arms and 
legs. EPA has set the drinking water standard for selenium at 0.05 parts 
per million (ppm) to protect against the risk of these adverse health 
effects. Drinking water that meets the EPA standard is associated with 
little to none of this risk and is considered safe with respect to 
selenium.
    (23) Acrylamide. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that acrylamide 
is a health concern at certain levels of exposure. Polymers made from 
acrylamide are sometimes used to treat water supplies to remove 
particulate contaminants. Acrylamide has been shown to cause cancer in 
laboratory animals such as rats and mice when the animals are exposed at 
high levels over their lifetimes. Chemicals that cause cancer in 
laboratory animals also may increase the risk of cancer in humans who 
are exposed over long periods of time. Sufficiently large doses of 
acrylamide are known to cause neurological injury. EPA has set the 
drinking water standard for acrylamide using a treatment technique to 
reduce the risk of cancer or other adverse health effects which have 
been observed in laboratory animals. This treatment technique limits the 
amount of acrylamide in the polymer and the amount of the polymer which 
may be added to drinking water to remove particulates. Drinking water 
systems which comply with this treatment technique have little to no 
risk and are considered safe with respect to acrylamide.
    (24) Alachlor. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that alachlor is 
a health concern at certain levels of exposure. This organic chemical is 
a widely used pesticide. When soil and climatic conditions are 
favorable, alachlor may get into drinking water by runoff into surface 
water or by leaching into ground water. This chemical has been shown to 
cause cancer in laboratory animals such as rats and mice when the 
animals are exposed at high levels over their lifetimes. Chemicals that 
cause cancer in laboratory animals also may increase the risk of cancer 
in humans who are exposed over long periods of time. EPA has set the 
drinking water standard for alachlor at 0.002 parts per million (ppm) to 
reduce the risk of cancer or other adverse health effects which have 
been observed in laboratory animals. Drinking water that meets this 
standard is associated with little to none of this risk and is 
considered safe with respect to alachlor.
    (25) Aldicarb. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that aldicarb is 
a health

[[Page 404]]

concern at certain levels of exposure. Aldicarb is a widely used 
pesticide. Under certain soil and climatic conditions (e.g., sandy soil 
and high rainfall), aldicarb may leach into ground water after normal 
agricultural applications to crops such as potatoes or peanuts or may 
enter drinking water supplies as a result of surface runoff. This 
chemical has been shown to damage the nervous system in laboratory 
animals such as rats and dogs exposed to high levels. EPA has set the 
drinking water standard for aldicarb at 0.003 parts per million (ppm) to 
protect against the risk of adverse health effects. Drinking water that 
meets the EPA standard is associated with little to none of this risk 
and is considered safe with respect to aldicarb.
    (26) Aldicarb sulfoxide. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that 
aldicarb sulfoxide is a health concern at certain levels of exposure. 
Aldicarb is a widely used pesticide. Aldicarb sulfoxide in ground water 
is primarily a breakdown product of aldicarb. Under certain soil and 
climatic conditions (e.g., sandy soil and high rainfall), aldicarb 
sulfoxide may leach into ground water after normal agricultural 
applications to crops such as potatoes or peanuts or may enter drinking 
water supplies as a result of surface runoff. This chemical has been 
shown to damage the nervous system in laboratory animals such as rats 
and dogs exposed to high levels. EPA has set the drinking water standard 
for aldicarb sulfoxide at 0.004 parts per million (ppm) to protect 
against the risk of adverse health effects. Drinking water that meets 
the EPA standard is associated with little to none of this risk and is 
considered safe with respect to aldicarb sulfoxide.
    (27) Aldicarb sulfone. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that 
aldicarb sulfone is a health concern at certain levels of exposure. 
Aldicarb is a widely used pesticide. Aldicarb sulfone is formed from the 
breakdown of aldicarb and is considered for registration as a pesticide 
under the name aldoxycarb. Under certain soil and climatic conditions 
(e.g., sandy soil and high rainfall), aldicarb sulfone may leach into 
ground water after normal agricultural applications to crops such as 
potatoes or peanuts or may enter drinking water supplies as a result of 
surface runoff. This chemical has been shown to damage the nervous 
system in laboratory animals such as rats and dogs exposed to high 
levels. EPA has set the drinking water standard for aldicarb sulfone at 
0.002 parts per million (ppm) to protect against the risk of adverse 
health effects. Drinking water that meets the EPA standard is associated 
with little to none of this risk and is considered safe with respect to 
aldicarb sulfone.
    (28) Atrazine. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that atrazine is 
a health concern at certain levels of exposure. This organic chemical is 
a herbicide. When soil and climatic conditions are favorable, atrazine 
may get into drinking water by runoff into surface water or by leaching 
into ground water. This chemical has been shown to affect offspring of 
rats and the heart of dogs. EPA has set the drinking water standard for 
atrazine at 0.003 parts per million (ppm) to protect against the risk of 
these adverse health effects. Drinking water that meets the EPA standard 
is associated with little to none of this risk and is considered safe 
with respect to atrazine.
    (29) Carbofuran. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that carbofuran 
is a health concern at certain levels of exposure. This organic chemical 
is a pesticide. When soil and climatic conditions are favorable, 
carbofuran may get into drinking water by runoff into surface water or 
by leaching into ground water. This chemical has been shown to damage 
the nervous and reproductive systems of laboratory animals such as rats 
and mice exposed at high levels over their lifetimes. Some humans who 
were exposed to relatively large amounts of this chemical during their 
working careers also suffered damage to the nervous system. Effects on 
the nervous system are generally rapidly reversible. EPA has set the

[[Page 405]]

drinking water standard for carbofuran at 0.04 parts per million (ppm) 
to protect against the risk of these adverse health effects. Drinking 
water that meets the EPA standard is associated with little to none of 
this risk and is considered safe with respect to carbofuran.
    (30) Chlordane. The United States Environmental Protection Agency 
(EPA sets drinking water standards and has determined that chlordane is 
a health concern at certain levels of exposure. This organic chemical is 
a pesticide used to control termites. Chlordane is not very mobile in 
soils. It usually gets into drinking water after application near water 
supply intakes or wells. This chemical has been shown to cause cancer in 
laboratory animals such as rats and mice when the animals are exposed at 
high levels over their lifetimes. Chemicals that cause cancer in 
laboratory animals also may increase the risk of cancer in humans who 
are exposed over long periods of time. EPA has set the drinking water 
standard for chlordane at 0.002 parts per million (ppm) to reduce the 
risk of cancer or other adverse health effects which have been observed 
in laboratory animals. Drinking water that meets the EPA standard is 
associated with little to none of this risk and is considered safe with 
respect to chlordane.
    (31) Dibromochloropropane (DBCP). The United States Environmental 
Protection Agency (EPA) sets drinking water standards and has determined 
that DBCP is a health concern at certain levels of exposure. This 
organic chemical was once a popular pesticide. When soil and climatic 
conditions are favorable, dibromochloropropane may get into drinking 
water by runoff into surface water or by leaching into ground water. 
This chemical has been shown to cause cancer in laboratory animals such 
as rats and mice when the animals are exposed at high levels over their 
lifetimes. Chemicals that cause cancer in laboratory animals also may 
increase the risk of cancer in humans who are exposed over long periods 
of time. EPA has set the drinking water standard for DBCP at 0.0002 
parts per million (ppm) to reduce the risk of cancer or other adverse 
health effects which have been observed in laboratory animals. Drinking 
water that meets the EPA standard is associated with little to none of 
this risk and is considered safe with respect to DBCP.
    (32) o-Dichlorobenzene. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that o-
dichlorobenzene is a health concern at certain levels of exposure. This 
organic chemical is used as a solvent in the production of pesticides 
and dyes. It generally gets into water by improper waste disposal. This 
chemical has been shown to damage the liver, kidney and the blood cells 
of laboratory animals such as rats and mice exposed to high levels 
during their lifetimes. Some industrial workers who were exposed to 
relatively large amounts of this chemical during working careers also 
suffered damage to the liver, nervous system, and circulatory system. 
EPA has set the drinking water standard for o-dichlorobenzene at 0.6 
parts per million (ppm) to protect against the risk of these adverse 
health effects. Drinking water that meets the EPA standard is associated 
with little to none of this risk and is considered safe with respect to 
o-dichlorobenzene.
    (33) cis-1,2-Dichloroethylene. The United States Environmental 
Protection Agency (EPA) establishes drinking water standards and has 
determined that cis-1,2-dichloroethylene is a health concern at certain 
levels of exposure. This organic chemical is used as a solvent and 
intermediate in chemical production. It generally gets into water by 
improper waste disposal. This chemical has been shown to damage the 
liver, nervous system, and circulatory system of laboratory animals such 
as rats and mice when exposed at high levels over their lifetimes. Some 
humans who were exposed to relatively large amounts of this chemical 
also suffered damage to the nervous system. EPA has set the drinking 
water standard for cis-1,2-dichloroethylene at 0.07 parts per million 
(ppm) to protect against the risk of these adverse health effects. 
Drinking water that meets the EPA standard is associated with little to 
none of this risk and is considered safe with respect to cis-1,2-
dichloroethylene.

[[Page 406]]

    (34) trans-1,2-Dichloroethylene. The United States Environmental 
Protection Agency (EPA) establishes drinking water standards and has 
determined that trans-1,2-dichloroethylene is a health concern at 
certain levels of exposure. This organic chemical is used as a solvent 
and intermediate in chemical production. It generally gets into water by 
improper waste disposal. This chemical has been shown to damage the 
liver, nervous system, and the circulatory system of laboratory animals 
such as rats and mice when exposed at high levels over their lifetimes. 
Some humans who were exposed to relatively large amounts of this 
chemical also suffered damage to the nervous system. EPA has set 
drinking water standard for trans-1,2-dichloroethylene at 0.1 parts per 
million (ppm) to protect against the risk of these adverse health 
effects. Drinking water that meets the EPA standard is associated with 
little to none of this risk and is considered safe with respect to 
trans-1,2-dichloroethylene.
    (35) 1,2-Dichloropropane. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that 1,2-
dichloropropane is a health concern at certain levels of exposure. This 
organic chemical is used as a solvent and pesticide. When soil and 
climatic conditions are favorable, 1,2-dichloropropane may get into 
drinking water by runoff into surface water or by leaching into ground 
water. It may also get into drinking water through improper waste 
disposal. This chemical has been shown to cause cancer in laboratory 
animals such as rats and mice when the animals are exposed at high 
levels over their lifetimes. Chemicals that cause cancer in laboratory 
animals also may increase the risk of cancer in humans who are exposed 
over long periods of time. EPA has set the drinking water standard for 
1,2-dichloropropane at 0.005 parts per million (ppm) to reduce the risk 
of cancer or other adverse health effects which have been observed in 
laboratory animals. Drinking water that meets the EPA standard is 
associated with little to none of this risk and is considered safe with 
respect to 1,2-dichloropropane.
    (36) 2,4-D. The United States Environmental Protection Agency (EPA) 
sets drinking water standards and has determined that 2,4-D is a health 
concern at certain levels of exposure. This organic chemical is used as 
a herbicide and to control algae in reservoirs. When soil and climatic 
conditions are favorable, 2,4-D may get into drinking water by runoff 
into surface water or by leaching into ground water. This chemical has 
been shown to damage the liver and kidney of laboratory animals such as 
rats exposed at high levels during their lifetimes. Some humans who were 
exposed to relatively large amounts of this chemical also suffered 
damage to the nervous system. EPA has set the drinking water standard 
for 2,4-D at 0.07 parts per million (ppm) to protect against the risk of 
these adverse health effects. Drinking water that meets the EPA standard 
is associated with little to none of this risk and is considered safe 
with respect to 2,4-D.
    (37) Epichlorohydrin. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that 
epichlorohydrin is a health concern at certain levels of exposure. 
Polymers made from epichlorohydrin are sometimes used in the treatment 
of water supplies as a flocculent to remove particulates. 
Epichlorohydrin generally gets into drinking water by improper use of 
these polymers. This chemical has been shown to cause cancer in 
laboratory animals such as rats and mice when the animals are exposed at 
high levels over their lifetimes. Chemicals that cause cancer in 
laboratory animals also may increase the risk of cancer in humans who 
are exposed over long periods of time. EPA has set the drinking water 
standard for epichlorohydrin using a treatment technique to reduce the 
risk of cancer or other adverse health effects which have been observed 
in laboratory animals. This treatment technique limits the amount of 
epichlorohydrin in the polymer and the amount of the polymer which may 
be added to drinking water as a flocculent to remove particulates. 
Drinking water systems which comply with this treatment technique

[[Page 407]]

have little to no risk and are considered safe with respect to 
epichlorohydrin.
    (38) Ethylbenzene. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined ethylbenzene is a 
health concern at certain levels of exposure. This organic chemical is a 
major component of gasoline. It generally gets into water by improper 
waste disposal or leaking gasoline tanks. This chemical has been shown 
to damage the kidney, liver, and nervous system of laboratory animals 
such as rats exposed to high levels during their lifetimes. EPA has set 
the drinking water standard for ethylbenzene at 0.7 part per million 
(ppm) to protect against the risk of these adverse health effects. 
Drinking water that meets the EPA standard is associated with little to 
none of this risk and is considered safe with respect to ethylbenzene.
    (39) Ethylene dibromide (EDB). The United States Environmental 
Protection Agency (EPA) sets drinking water standards and has determined 
that EDB is a health concern at certain levels of exposure. This organic 
chemical was once a popular pesticide. When soil and climatic conditions 
are favorable, EDB may get into drinking water by runoff into surface 
water or by leaching into ground water. This chemical has been shown to 
cause cancer in laboratory animals such as rats and mice when the 
animals are exposed at high levels over their lifetimes. Chemicals that 
cause cancer in laboratory animals also may increase the risk of cancer 
in humans who are exposed over long periods of time. EPA has set the 
drinking water standard for EDB at 0.00005 part per million (ppm) to 
reduce the risk of cancer or other adverse health effects which have 
been observed in laboratory animals. Drinking water that meets this 
standard is associated with little to none of this risk and is 
considered safe with respect to EDB.
    (40) Heptachlor. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that heptachlor 
is a health concern at certain levels of exposure. This organic chemical 
was once a popular pesticide. When soil and climatic conditions are 
favorable, heptachlor may get into drinking water by runoff into surface 
water or by leaching into ground water. This chemical has been shown to 
cause cancer in laboratory animals such as rats and mice when the 
animals are exposed at high levels over their lifetimes. Chemicals that 
cause cancer in laboratory animals also may increase the risk of cancer 
in humans who are exposed over long periods of time. EPA has set the 
drinking water standards for heptachlor at 0.0004 part per million (ppm) 
to reduce the risk of cancer or other adverse health effects which have 
been observed in laboratory animals. Drinking water that meets this 
standard is associated with little to none of this risk and is 
considered safe with respect to heptachlor.
    (41) Heptachlor epoxide. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that 
heptachlor epoxide is a health concern at certain levels of exposure. 
This organic chemical was once a popular pesticide. When soil and 
climatic conditions are favorable, heptachlor expoxide may get into 
drinking water by runoff into surface water or by leaching into ground 
water. This chemical has been shown to cause cancer in laboratory 
animals such as rats and mice when the animals are exposed at high 
levels over their lifetimes. Chemicals that cause cancer in laboratory 
animals also may increase the risk of cancer in humans who are exposed 
over long periods of time. EPA has set the drinking water standards for 
heptachlor epoxide at 0.0002 part per million (ppm) to reduce the risk 
of cancer or other adverse health effects which have been observed in 
laboratory animals. Drinking water that meets this standard is 
associated with little to none of this risk and is considered safe with 
respect to heptachlor epoxide.
    (42) Lindane. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that lindane is a 
health concern at certain levels of exposure. This organic chemical is 
used as a pesticide. When soil and climatic conditions are favorable, 
lindane may get

[[Page 408]]

into drinking water by runoff into surface water or by leaching into 
ground water. This chemical has been shown to damage the liver, kidney, 
nervous system, and immune system of laboratory animals such as rats, 
mice and dogs exposed at high levels during their lifetimes. Some humans 
who were exposed to relatively large amounts of this chemical also 
suffered damage to the nervous system and circulatory system. EPA has 
established the drinking water standard for lindane at 0.0002 part per 
million (ppm) to protect against the risk of these adverse health 
effects. Drinking water that meets the EPA standard is associated with 
little to none of this risk and is considered safe with respect to 
lindane.
    (43) Methoxychlor. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that methoxychlor 
is a health concern at certain levels of exposure. This organic chemical 
is used as a pesticide. When soil and climatic conditions are favorable, 
methoxychlor may get into drinking water by runoff into surface water or 
by leaching into ground water. This chemical has been shown to damage 
the liver, kidney, nervous system, and reproductive system of laboratory 
animals such as rats exposed at high levels during their lifetimes. It 
has also been shown to produce growth retardation in rats. EPA has set 
the drinking water standard for methoxychlor at 0.04 part per million 
(ppm) to protect against the risk of these adverse health effects. 
Drinking water that meets the EPA standard is associated with little to 
none of this risk and is considered safe with respect to methoxychlor.
    (44) Monochlorobenzene. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that 
monochlorobenzene is a health concern at certain levels of exposure. 
This organic chemical is used as a solvent. It generally gets into water 
by improper waste disposal. This chemical has been shown to damage the 
liver, kidney and nervous system of laboratory animals such as rats and 
mice exposed to high levels during their lifetimes. EPA has set the 
drinking water standard for monochlorobenzene at 0.1 part per million 
(ppm) to protect against the risk of these adverse health effects. 
Drinking water that meets the EPA standard is associated with little to 
none of this risk and is considered safe with respect to 
monochlorobenzene.
    (45) Polychlorinated biphenyls (PCBs). The United States 
Environmental Protection Agency (EPA) sets drinking water standards and 
has determined that polychlorinated biphenyls (PCBs) are a health 
concern at certain levels of exposure. These organic chemicals were once 
widely used in electrical transformers and other industrial equipment. 
They generally get into drinking water by improper waste disposal or 
leaking electrical industrial equipment. This chemical has been shown to 
cause cancer in laboratory animals such as rats and mice when the 
animals are exposed at high levels over their lifetimes. Chemicals that 
cause cancer in laboratory animals also may increase the risk of cancer 
in humans who are exposed over long periods of time. EPA has set the 
drinking water standard for PCBs at 0.0005 part per million (ppm) to 
reduce the risk of cancer or other adverse health effects which have 
been observed in laboratory animals. Drinking water that meets this 
standard is associated with little to none of this risk and is 
considered safe with respect to PCBs.
    (46) Pentachlorophenol. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that 
pentachlorophenol is a health concern at certain levels of exposure. 
This organic chemical is used as a wood preservative, herbicide, 
disinfectant, and defoliant. It generally gets into drinking water by 
runoff into surface water or leaching into ground water. This chemical 
has been shown to produce adverse reproductive effects and to damage the 
liver and kidneys of laboratory animals such as rats exposed to high 
levels during their lifetimes. Some humans who were exposed to 
relatively large amounts of this chemical also suffered damage to the 
liver and kidneys. This chemical has been shown to cause cancer in 
laboratory animals such as rats and mice when the animals are exposed to 
high levels over their lifetimes. Chemicals that cause

[[Page 409]]

cancer in laboratory animals also may increase the risk of cancer in 
humans who are exposed over long periods of time. EPA has set the 
drinking water standard for pentachlorophenol at 0.001 parts per million 
(ppm) to protect against the risk of cancer or other adverse health 
effects. Drinking water that meets the EPA standard is associated with 
little to none of this risk and is considered safe with respect to 
pentachlorophenol.
    (47) Styrene. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that styrene is a 
health concern at certain levels of exposure. This organic chemical is 
commonly used to make plastics and is sometimes a component of resins 
used for drinking water treatment. Styrene may get into drinking water 
from improper waste disposal. This chemical has been shown to damage the 
liver and nervous system in laboratory animals when exposed at high 
levels during their lifetimes. EPA has set the drinking water standard 
for styrene at 0.1 part per million (ppm) to protect against the risk of 
these adverse health effects. Drinking water that meets the EPA standard 
is associated with little to none of this risk and is considered safe 
with respect to styrene.
    (48) Tetrachloroethylene. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that 
tetrachloroethylene is a health concern at certain levels of exposure. 
This organic chemical has been a popular solvent, particularly for dry 
cleaning. It generally gets into drinking water by improper waste 
disposal. This chemical has been shown to cause cancer in laboratory 
animals such as rats and mice when the animals are exposed at high 
levels over their lifetimes. Chemicals that cause cancer in laboratory 
animals also may increase the risk of cancer in humans who are exposed 
over long periods of time. EPA has set the drinking water standard for 
tetrachloroethylene at 0.005 part per million (ppm) to reduce the risk 
of cancer or other adverse health effects which have been observed in 
laboratory animals. Drinking water that meets this standard is 
associated with little to none of this risk and is considered safe with 
respect to tetrachloroethylene.
    (49) Toluene. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that toluene is a 
health concern at certain levels of exposure. This organic chemical is 
used as a solvent and in the manufacture of gasoline for airplanes. It 
generally gets into water by improper waste disposal or leaking 
underground storage tanks. This chemical has been shown to damage the 
kidney, nervous system, and circulatory system of laboratory animals 
such as rats and mice exposed to high levels during their lifetimes. 
Some industrial workers who were exposed to relatively large amounts of 
this chemical during working careers also suffered damage to the liver, 
kidney and nervous system. EPA has set the drinking water standard for 
toluene at 1 part per million (ppm) to protect against the risk of 
adverse health effects. Drinking water that meets the EPA standard is 
associated with little to none of this risk and is considered safe with 
respect to toluene.
    (50) Toxaphene. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that toxaphene is 
a health concern at certain levels of exposure. This organic chemical 
was once a pesticide widely used on cotton, corn, soybeans, pineapples 
and other crops. When soil and climatic conditions are favorable, 
toxaphene may get into drinking water by runoff into surface water or by 
leaching into ground water. This chemical has been shown to cause cancer 
in laboratory animals such as rats and mice when the animals are exposed 
at high levels over their lifetimes. Chemicals that cause cancer in 
laboratory animals also may increase the risk of cancer in humans who 
are exposed over long periods of time. EPA has set the drinking water 
standard for toxaphene at 0.003 part per million (ppm) to reduce the 
risk of cancer or other adverse health effects which have been observed 
in laboratory animals. Drinking water that meets this standard is 
associated with little to none of this risk and is considered safe with 
respect to toxaphene.

[[Page 410]]

    (51) 2,4,5-TP. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that 2,4,5-TP is 
a health concern at certain levels of exposure. This organic chemical is 
used as a herbicide. When soil and climatic conditions are favorable, 
2,4,5-TP may get into drinking water by runoff into surface water or by 
leaching into ground water. This chemical has been shown to damage the 
liver and kidney of laboratory animals such as rats and dogs exposed to 
high levels during their lifetimes. Some industrial workers who were 
exposed to relatively large amounts of this chemical during working 
careers also suffered damage to the nervous system. EPA has set the 
drinking water standard for 2,4,5-TP at 0.05 part per million (ppm) to 
protect against the risk of these adverse health effects. Drinking water 
that meets the EPA standard is associated with little to none of this 
risk and is considered safe with respect to 2,4,5-TP.
    (52) Xylenes. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that xylene is a 
health concern at certain levels of exposure. This organic chemical is 
used in the manufacture of gasoline for airplanes and as a solvent for 
pesticides, and as a cleaner and degreaser of metals. It usually gets 
into water by improper waste disposal. This chemical has been shown to 
damage the liver, kidney and nervous system of laboratory animals such 
as rats and dogs exposed to high levels during their lifetimes. Some 
humans who were exposed to relatively large amounts of this chemical 
also suffered damage to the nervous system. EPA has set the drinking 
water standard for xylene at 10 parts per million (ppm) to protect 
against the risk of these adverse health effects. Drinking water that 
meets the EPA standard is associated with little to none of this risk 
and is considered safe with respect to xylene.
    (53) Antimony. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that antimony is 
a health concern at certain levels of exposure. This inorganic chemical 
occurs naturally in soils, ground water and surface waters and is often 
used in the flame retardant industry. It is also used in ceramics, 
glass, batteries, fireworks and explosives. It may get into drinking 
water through natural weathering of rock, industrial production, 
municipal waste disposal or manufacturing processes. This chemical has 
been shown to decrease longevity, and altered blood levels of 
cholesterol and glucose in laboratory animals such as rats exposed to 
high levels during their lifetimes. EPA has set the drinking water 
standard for antimony at 0.006 parts per million (ppm) to protect 
against the risk of these adverse health effects. Drinking water which 
meets the EPA standard is associated with little to none of this risk 
and should be considered safe with respect to antimony.
    (54) Beryllium. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that beryllium is 
a health concern at certain levels of exposure. This inorganic metal 
occurs naturally in soils, ground water and surface waters and is often 
used in electrical equipment and electrical components. It generally 
gets into water from runoff from mining operations, discharge from 
processing plants and improper waste disposal. Beryllium compounds have 
been associated with damage to the bones and lungs and induction of 
cancer in laboratory animals such as rats and mice when the animals are 
exposed at high levels over their lifetimes. There is limited evidence 
to suggest that beryllium may pose a cancer risk via drinking water 
exposure. Therefore, EPA based the health assessment on noncancer 
effects with an extra uncertainty factor to account for possible 
carcinogenicity. Chemicals that cause cancer in laboratory animals also 
may increase the risk of cancer in humans who are exposed over long 
periods of time. EPA has set the drinking water standard for beryllium 
at 0.004 part per million (ppm) to protect against the risk of these 
adverse health effects. Drinking water which meets the EPA standard is 
associated with little to none of this risk and should be considered 
safe with respect to beryllium.

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    (55) Cyanide. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that cyanide is a 
health concern at certain levels of exposure. This inorganic chemical is 
used in electroplating, steel processing, plastics, synthetic fabrics 
and fertilizer products. It usually gets into water as a result of 
improper waste disposal. This chemical has been shown to damage the 
spleen, brain and liver of humans fatally poisoned with cyanide. EPA has 
set the drinking water standard for cyanide at 0.2 parts per million 
(ppm) to protect against the risk of these adverse health effects. 
Drinking water which meets the EPA standard is associated with little to 
none of this risk and should be considered safe with respect to cyanide.
    (56) [Reserved]
    (57) Thallium. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that thallium is 
a health concern at certain high levels of exposure. This inorganic 
metal is found naturally in soils and is used in electronics, 
pharmaceuticals, and the manufacture of glass and alloys. This chemical 
has been shown to damage the kidney, liver, brain and intestines of 
laboratory animals when the animals are exposed at high levels over 
their lifetimes. EPA has set the drinking water standard for thallium at 
0.002 parts per million (ppm) to protect against the risk of these 
adverse health effects. Drinking water which meets the EPA standard is 
associated with little to none of this risk and should be considered 
safe with respect to thallium.
    (58) Benzo[a]pyrene. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that 
benzo[a]pyrene is a health concern at certain levels of exposure. 
Cigarette smoke and charbroiled meats are common source of general 
exposure. The major source of benzo[a]pyrene in drinking water is the 
leaching from coal tar lining and sealants in water storage tanks. This 
chemical has been shown to cause cancer in animals such as rats and mice 
when the animals are exposed at high levels. EPA has set the drinking 
water standard for benzo[a]pyrene at 0.0002 parts per million (ppm) to 
protect against the risk of cancer. Drinking water which meets the EPA 
standard is associated with little to none of this risk and should be 
considered safe with respect to benzo[a]pyrene.
    (59) Dalapon. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that dalapon is a 
health concern at certain levels of exposure. This organic chemical is a 
widely used herbicide. It may get into drinking water after application 
to control grasses in crops, drainage ditches and along railroads. This 
chemical has been shown to cause damage to the kidney and liver in 
laboratory animals when the animals are exposed to high levels over 
their lifetimes. EPA has set the drinking water standard for dalapon at 
0.2 parts per million (ppm) to protect against the risk of these adverse 
health effects. Drinking water which meets the EPA standard is 
associated with little to none of this risk and should be considered 
safe with respect to dalapon.
    (60) Dichloromethane. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that 
dichloromethane (methylene chloride) is a health concern at certain 
levels of exposure. This organic chemical is a widely used solvent. It 
is used in the manufacture of paint remover, as a metal degreaser and as 
an aerosol propellant. It generally gets into drinking water after 
improper discharge of waste disposal. This chemical has been shown to 
cause cancer in laboratory animals such as rats and mice when the 
animals are exposed at high levels over their lifetimes. Chemicals that 
cause cancer in laboratory animals also may increase the risk of cancer 
in humans who are exposed over long periods of time. EPA has set the 
drinking water standard for dichloromethane at 0.005 parts per million 
(ppm) to reduce the risk of cancer or other adverse health effects which 
have been observed in laboratory animals. Drinking water which meets 
this standard is associated with little to none of this risk

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and should be considered safe with respect to dichloromethane.
    (61) Di (2-ethylhexyl)adipate. The United States Environmental 
Protection Agency (EPA) sets drinking water standards and has determined 
that di(2-ethylhexyl)adipate is a health concern at certain levels of 
exposure. Di(2-ethylhexyl)adipate is a widely used plasticizer in a 
variety of products, including synthetic rubber, food packaging 
materials and cosmetics. It may get into drinking water after improper 
waste disposal. This chemical has been shown to damage liver and testes 
in laboratory animals such as rats and mice exposed to high levels. EPA 
has set the drinking water standard for di(2-ethylhexyl)adipate at 0.4 
parts per million (ppm) to protect against the risk of adverse health 
effects. Drinking water which meets the EPA standards is associated with 
little to none of this risk and should be considered safe with respect 
to di(2-ethylhexyl)adipate.
    (62) Di(2-ethylhexyl)phthalate. The United States Environmental 
Protection Agency (EPA) sets drinking water standards and has determined 
that di(2-ethylhexyl)phthalate is a health concern at certain levels of 
exposure. Di(2-ethylhexyl)phthalate is a widely used plasticizer, which 
is primarily used in the production of polyvinyl chloride (PVC) resins. 
It may get into drinking water after improper waste disposal. This 
chemical has been shown to cause cancer in laboratory animals such as 
rats and mice exposed to high levels over their lifetimes. EPA has set 
the drinking water standard for di(2-ethylhexyl)phthalate at 0.006 parts 
per million (ppm) to reduce the risk of cancer or other adverse health 
effects which have been observed in laboratory animals. Drinking water 
which meets the EPA standard is associated with little to none of this 
risk and should be considered safe with respect to di(2-
ethylhexyl)phthalate.
    (63) Dinoseb. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that dinoseb is a 
health concern at certain levels of exposure. Dinoseb is a widely used 
pesticide and generally gets into drinking water after application on 
orchards, vineyards and other crops. This chemical has been shown to 
damage the thyroid and reproductive organs in laboratory animals such as 
rats exposed to high levels. EPA has set the drinking water standard for 
dinoseb at 0.007 parts per million (ppm) to protect against the risk of 
adverse health effects. Drinking water which meets the EPA standard is 
associated with little to none of this risk and should be considered 
safe with respect to dinoseb.
    (64) Diquat. The United States Environmental Protection Agency (EPA) 
sets drinking water standards and has determined that diquat is a health 
concern at certain levels of exposure. This organic chemical is a 
herbicide used to control terrestrial and aquatic weeds. It may get into 
drinking water by runoff into surface water. This chemical has been 
shown to damage the liver, kidney and gastrointestinal tract and causes 
cataract formation in laboratory animals such as dogs and rats exposed 
at high levels over their lifetimes. EPA has set the drinking water 
standard for diquat at 0.02 parts per million (ppm) to protect against 
the risk of these adverse health effects. Drinking water which meets the 
EPA standard is associated with little to none of this risk and should 
be considered safe with respect to diquat.
    (65) Endothall. The United States Environmental Protection Agency 
(EPA) has determined that endothall is a health concern at certain 
levels of exposure. This organic chemical is a herbicide used to control 
terrestrial and aquatic weeds. It may get into water by runoff into 
surface water. This chemical has been shown to damage the liver, kidney, 
gastrointestinal tract and reproductive system of laboratory animals 
such as rats and mice exposed at high levels over their lifetimes. EPA 
has set the drinking water standard for endothall at 0.1 parts per 
million (ppm) to protect against the risk of these adverse health 
effects. Drinking water which meets the EPA standard is associated with 
little to none of this risk and should be considered safe with respect 
to endothall.
    (66) Endrin. The United States Environmental Protection Agency (EPA) 
sets drinking water standards and has determined that endrin is a health 
concern at certain levels of exposure. This

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organic chemical is a pesticide no longer registered for use in the 
United States. However, this chemical is persistent in treated soils and 
accumulates in sediments and aquatic and terrestrial biota. This 
chemical has been shown to cause damage to the liver, kidney and heart 
in laboratory animals such as rats and mice when the animals are exposed 
at high levels over their lifetimes. EPA has set the drinking water 
standard for endrin at 0.002 parts per million (ppm) to protect against 
the risk of these adverse health effects which have been observed in 
laboratory animals. Drinking water that meets the EPA standard is 
associated with little to none of this risk and should be considered 
safe with respect to endrin.
    (67) Glyphosate. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that glyphosate 
is a health concern at certain levels of exposure. This organic chemical 
is a herbicide used to control grasses and weeds. It may get into 
drinking water by runoff into surface water. This chemical has been 
shown to cause damage to the liver and kidneys in laboratory animals 
such as rats and mice when the animals are exposed at high levels over 
their lifetimes. EPA has set the drinking water standard for glyphosate 
at 0.7 parts per million (ppm) to protect against the risk of these 
adverse health effects. Drinking water which meets the EPA standard is 
associated with little to none of this risk and should be considered 
safe with respect to glyphosate.
    (68) Hexachlorobenzene. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that 
hexachlorobenzene is a health concern at certain levels of exposure. 
This organic chemical is produced as an impurity in the manufacture of 
certain solvents and pesticides. This chemical has been shown to cause 
cancer in laboratory animals such as rats and mice when the animals are 
exposed to high levels during their lifetimes. Chemicals that cause 
cancer in laboratory animals also may increase the risk of cancer in 
humans who are exposed over long periods of time. EPA has set the 
drinking water standard for hexachlorobenzene at 0.001 parts per million 
(ppm) to protect against the risk of cancer and other adverse health 
effects. Drinking water which meets the EPA standard is associated with 
little to none of this risk and should be considered safe with respect 
to hexachlorobenzene.
    (69) Hexachlorocyclopentadiene. The United States Environmental 
Protection Agency (EPA) establishes drinking water standards and has 
determined that hexachlorocyclopentadiene is a health concern at certain 
levels of exposure. This organic chemical is used as an intermediate in 
the manufacture of pesticides and flame retardants. It may get into 
water by discharge from production facilities. This chemical has been 
shown to damage the kidney and the stomach of laboratory animals when 
exposed at high levels over their lifetimes. EPA has set the drinking 
water standard for hexachlorocyclopentadiene at 0.05 parts per million 
(ppm) to protect against the risk of these adverse health effects. 
Drinking water which meets the EPA standard is associated with little to 
none of this risk and should be considered safe with respect to 
hexachlorocyclopentadiene.
    (70) Oxamyl. The United States Environmental Protection Agency (EPA) 
establishes drinking water standards and has determined that oxamyl is a 
health concern at certain levels of exposure. This organic chemical is 
used as a pesticide for the control of insects and other pests. It may 
get into drinking water by runoff into surface water or leaching into 
ground water. This chemical has been shown to damage the kidneys of 
laboratory animals such as rats when exposed at high levels over their 
lifetimes. EPA has set the drinking water standard for oxamyl at 0.2 
parts per million (ppm) to protect against the risk of these adverse 
health effects. Drinking water which meets the EPA standard is 
associated with little to none of this risk and should be considered 
safe with respect to oxamyl.
    (71) Picloram. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that picloram is 
a health concern at certain levels of exposure.

[[Page 414]]

This organic chemical is used as a pesticide for broadleaf weed control. 
It may get into drinking water by runoff into surface water or leaching 
into ground water as a result of pesticide application and improper 
waste disposal. This chemical has been shown to cause damage to the 
kidneys and liver in laboratory animals such as rats when the animals 
are exposed at high levels over their lifetimes. EPA has set the 
drinking water standard for picloram at 0.5 parts per million (ppm) to 
protect against the risk of these adverse health effects. Drinking water 
which meets the EPA standard is associated with little to none of this 
risk and should be considered safe with respect to picloram.
    (72) Simazine. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that simazine is 
a health concern at certain levels of exposure. This organic chemical is 
a herbicide used to control annual grasses and broadleaf weeds. It may 
leach into ground water or runs off into surface water after 
application. This chemical may cause cancer in laboratory animals such 
as rats and mice exposed at high levels during their lifetimes. 
Chemicals that cause cancer in laboratory animals also may increase the 
risk of cancer in humans who are exposed over long periods of time. EPA 
has set the drinking water standard for simazine at 0.004 parts per 
million (ppm) to reduce the risk of cancer or other adverse health 
effects. Drinking water which meets the EPA standard is associated with 
little to none of this risk and should be considered safe with respect 
to simazine.
    (73) 1,2,4-Trichlorobenzene. The United States Environmental 
Protection Agency (EPA) sets drinking water standards and has determined 
that 1,2,4-trichlorobenzene is a health concern at certain levels of 
exposure. This organic chemical is used as a dye carrier and as a 
precursor in herbicide manufacture. It generally gets into drinking 
water by discharges from industrial activities. This chemical has been 
shown to cause damage to several organs, including the adrenal glands. 
EPA has set the drinking water standard for 1,2,4-trichlorobenzene at 
0.07 parts per million (ppm) to protect against the risk of these 
adverse health effects. Drinking water which meets the EPA standard is 
associated with little to none of this risk and should be considered 
safe with respect to 1,2,4-trichlorobenzene.
    (74) 1,1,2-Trichloroethane. The United States Environmental 
Protection Agency (EPA) sets drinking water standards and has determined 
1,1,2-trichloroethane is a health concern at certain levels of exposure. 
This organic chemical is an intermediate in the production of 1,1-
dichloroethylene. It generally gets into water by industrial discharge 
of wastes. This chemical has been shown to damage the kidney and liver 
of laboratory animals such as rats exposed to high levels during their 
lifetimes. EPA has set the drinking water standard for 1,1,2-
trichloroethane at 0.005 parts per million (ppm) to protect against the 
risk of these adverse health effects. Drinking water which meets the EPA 
standard is associated with little to none of this risk and should be 
considered safe with respect to 1,1,2-trichloroethane.
    (75) 2,3,7,8-TCDD (Dioxin). The United States Environmental 
Protection Agency (EPA) sets drinking water standards and has determined 
that dioxin is a health concern at certain levels of exposure. This 
organic chemical is an impurity in the production of some pesticides. It 
may get into drinking water by industrial discharge of wastes. This 
chemical has been shown to cause cancer in laboratory animals such as 
rats and mice when the animals are exposed at high levels over their 
lifetimes. Chemicals that cause cancer in laboratory animals also may 
increase the risk of cancer in humans who are exposed over long periods 
of time. EPA has set the drinking water standard for dioxin at 
0.00000003 parts per million (ppm) to reduce the risk of cancer or other 
adverse health effects which have been observed in laboratory animals. 
Drinking water which meets this standard is associated with little to 
none of this risk and should be considered safe with respect to dioxin.
    (76) Chlorine. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that chlorine is 
a health

[[Page 415]]

concern at certain levels of exposure. Chlorine is added to drinking 
water as a disinfectant to kill bacteria and other disease-causing 
microorganisms and is also added to provide continuous disinfection 
throughout the distribution system. Disinfection is required for surface 
water systems. However, at high doses for extended periods of time, 
chlorine has been shown to affect blood and the liver in laboratory 
animals. EPA has set a drinking water standard for chlorine to protect 
against the risk of these adverse effects. Drinking water which meets 
this EPA standard is associated with little to none of this risk and 
should be considered safe with respect to chlorine.
    (77) Chloramines. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that chloramines 
are a health concern at certain levels of exposure. Chloramines are 
added to drinking water as a disinfectant to kill bacteria and other 
disease-causing microorganisms and are also added to provide continuous 
disinfection throughout the distribution system. Disinfection is 
required for surface water systems. However, at high doses for extended 
periods of time, chloramines have been shown to affect blood and the 
liver in laboratory animals. EPA has set a drinking water standard for 
chloramines to protect against the risk of these adverse effects. 
Drinking water which meets this EPA standard is associated with little 
to none of this risk and should be considered safe with respect to 
chloramines.
    (78) Chlorine dioxide. The United States Environmental Protection 
Agency (EPA) sets drinking water standards and has determined that 
chlorine dioxide is a health concern at certain levels of exposure. 
Chlorine dioxide is used in water treatment to kill bacteria and other 
disease-causing microorganisms and can be used to control tastes and 
odors. Disinfection is required for surface water systems. However, at 
high doses, chlorine dioxide-treated drinking water has been shown to 
affect blood in laboratory animals. Also, high levels of chlorine 
dioxide given to laboratory animals in drinking water have been shown to 
cause neurological effects on the developing nervous system. These 
neurodevelopmental effects may occur as a result of a short-term 
excessive chlorine dioxide exposure. To protect against such potentially 
harmful exposures, EPA requires chlorine dioxide monitoring at the 
treatment plant, where disinfection occurs, and at representative points 
in the distribution system serving water users. EPA has set a drinking 
water standard for chlorine dioxide to protect against the risk of these 
adverse effects.

    Note: In addition to the language in this introductory text of 
paragraph (e)(78), systems must include either the language in paragraph 
(e)(78)(i) or (e)(78)(ii) of this section. Systems with a violation at 
the treatment plant, but not in the distribution system, are required to 
use the language in paragraph (e)(78)(i) of this section and treat the 
violation as a nonacute violation. Systems with a violation in the 
distribution system are required to use the language in paragraph 
(e)(78)(ii) of this section and treat the violation as an acute 
violation.

    (i) The chlorine dioxide violations reported today are the result of 
exceedances at the treatment facility only, and do not include 
violations within the distribution system serving users of this water 
supply. Continued compliance with chlorine dioxide levels within the 
distribution system minimizes the potential risk of these violations to 
present consumers.
    (ii) The chlorine dioxide violations reported today include 
exceedances of the EPA standard within the distribution system serving 
water users. Violations of the chlorine dioxide standard within the 
distribution system may harm human health based on short-term exposures. 
Certain groups, including pregnant women, infants, and young children, 
may be especially susceptible to adverse effects of excessive exposure 
to chlorine dioxide-treated water. The purpose of this notice is to 
advise that such persons should consider reducing their risk of adverse 
effects from these chlorine dioxide violations by seeking alternate 
sources of water for human consumption until such exceedances are 
rectified. Local and State health authorities are the best sources for 
information concerning alternate drinking water.

[[Page 416]]

    (79) Disinfection byproducts and treatment technique for DBPs. The 
United States Environmental Protection Agency (EPA) sets drinking water 
standards and requires the disinfection of drinking water. However, when 
used in the treatment of drinking water, disinfectants react with 
naturally-occurring organic and inorganic matter present in water to 
form chemicals called disinfection byproducts (DBPs). EPA has determined 
that a number of DBPs are a health concern at certain levels of 
exposure. Certain DBPs, including some trihalomethanes (THMs) and some 
haloacetic acids (HAAs), have been shown to cause cancer in laboratory 
animals. Other DBPs have been shown to affect the liver and the nervous 
system, and cause reproductive or developmental effects in laboratory 
animals. Exposure to certain DBPs may produce similar effects in people. 
EPA has set standards to limit exposure to THMs, HAAs, and other DBPs.
    (80) Bromate. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that bromate is a 
health concern at certain levels of exposure. Bromate is formed as a 
byproduct of ozone disinfection of drinking water. Ozone reacts with 
naturally occurring bromide in the water to form bromate. Bromate has 
been shown to produce cancer in rats. EPA has set a drinking water 
standard to limit exposure to bromate.
    (81) Chlorite. The United States Environmental Protection Agency 
(EPA) sets drinking water standards and has determined that chlorite is 
a health concern at certain levels of exposure. Chlorite is formed from 
the breakdown of chlorine dioxide, a drinking water disinfectant. 
Chlorite in drinking water has been shown to affect blood and the 
developing nervous system. EPA has set a drinking water standard for 
chlorite to protect against these effects. Drinking water which meets 
this standard is associated with little to none of these risks and 
should be considered safe with respect to chlorite.
    (f) Public notices for fluoride. Notice of violations of the maximum 
contaminant level for fluoride, notices of variances and exemptions from 
the maximum contaminant level for fluoride, and notices of failure to 
comply with variance and exemption schedules for the maximum contaminant 
level for fluoride shall consist of the public notice prescribed in 
Sec. 143.5(b), plus a description of any steps which the system is 
taking to come into compliance.
    (g) Public notification by the State. The State may give notice to 
the public required by this section on behalf of the owner or operator 
of the public water system if the State complies with the requirements 
of this section. However, the owner or operator of the public water 
system remains legally responsible for ensuring that the requirements of 
this section are met.

[52 FR 41546, Oct. 28, 1987, as amended at 54 FR 15188, Apr. 17, 1989; 
54 FR 27527, 27566, June 29, 1989; 55 FR 25064, June 19, 1990; 56 FR 
3587, Jan. 30, 1991; 56 FR 26548, June 7, 1991; 56 FR 30279, July 1, 
1991; 57 FR 31843, July 17, 1992; 59 FR 34323, July 1, 1994; 60 FR 
33932, June 29, 1995; 63 FR 69464, 69515, Dec. 16, 1998; 65 FR 26022, 
May 4, 2000]