[Code of Federal Regulations]
[Title 40, Volume 24]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR280.52]

[Page 468-469]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
                           AGENCY (CONTINUED)
 
PART 280--TECHNICAL STANDARDS AND CORRECTIVE ACTION REQUIREMENTS FOR OWNERS AND OPERATORS OF UNDERGROUND STORAGE TANKS (UST)--Table of Contents
 
      Subpart E--Release Reporting, Investigation, and Confirmation
 
Sec. 280.52  Release investigation and confirmation steps.

    Unless corrective action is initiated in accordance with subpart F, 
owners and operators must immediately investigate and confirm all 
suspected releases of regulated substances requiring reporting under 
Sec. 280.50 within 7 days, or another reasonable time period specified 
by the implementing agency, using either the following steps or another 
procedure approved by the implementing agency:
    (a) System test. Owners and operators must conduct tests (according 
to the requirements for tightness testing in Sec. 280.43(c) and 
Sec. 280.44(b)) that determine whether a leak exists in that portion of 
the tank that routinely contains product, or the attached delivery 
piping, or both.
    (1) Owners and operators must repair, replace or upgrade the UST 
system,

[[Page 469]]

and begin corrective action in accordance with subpart F if the test 
results for the system, tank, or delivery piping indicate that a leak 
exists.
    (2) Further investigation is not required if the test results for 
the system, tank, and delivery piping do not indicate that a leak exists 
and if environmental contamination is not the basis for suspecting a 
release.
    (3) Owners and operators must conduct a site check as described in 
paragraph (b) of this section if the test results for the system, tank, 
and delivery piping do not indicate that a leak exists but environmental 
contamination is the basis for suspecting a release.
    (b) Site check. Owners and operators must measure for the presence 
of a release where contamination is most likely to be present at the UST 
site. In selecting sample types, sample locations, and measurement 
methods, owners and operators must consider the nature of the stored 
substance, the type of initial alarm or cause for suspicion, the type of 
backfill, the depth of ground water, and other factors appropriate for 
identifying the presence and source of the release.
    (1) If the test results for the excavation zone or the UST site 
indicate that a release has occurred, owners and operators must begin 
corrective action in accordance with subpart F;
    (2) If the test results for the excavation zone or the UST site do 
not indicate that a release has occurred, further investigation is not 
required.