Page 209 - California Stormwater Workshop Handouts

APPENDIX 2
INSTRUCTIONS FOR NO EXPOSURE CERTIFICATION (NEC)
ASTs to qualify for “No Exposure”, the following
must be satisfied:
i. The tank(s) shall be physically separated from
and not associated with vehicle maintenance
operations.
ii. There shall be no leaks from piping, pumps, or
other equipment that has the potential to come in
contact with storm water.
iii. Wherever feasible, the tank(s) shall have
secondary containment (e.g., an impervious dike,
berm or concrete retaining structure) to prevent
runoff in the event of a structural failure or leaking
transfer valve. Note: any resulting unpermitted
discharge is in violation of the CWA.
c. Lidded Dumpsters. Lidded dumpsters containing
waste materials, providing the containers are
completely covered and nothing can drain out holes
in the bottom, spilled when loaded into the
dumpster, or spilled in loading into a garbage truck.
Industrial waste materials and trash that is stored
uncovered is considered exposed.
d. Adequately maintained vehicles, such as trucks,
automobiles, forklifts, trailers or other general-
purpose vehicles found onsite - but not industrial
machinery that are not leaking, are in good repair or
are not otherwise a potential source of
contaminants:
i. Vehicles passing between buildings may be
exposed to storm water, however if the vehicles
are adequately maintained, a condition of
exposure may not exist. Similarly, non-leaking
vehicles awaiting maintenance at vehicle
maintenance facilities are not considered as
potential exposure. However, vehicles that have
been washed or rinsed that are not completely
dry prior to outside exposure have the potential to
cause a condition of exposure. Vehicles that
track materials out of the facility are considered to
be mobilizing pollutants. Vehicles that exit
maintenance bays are also considered to cause
exposure.
ii. The mere conveyance between buildings of
materials / products that are otherwise not
allowed to be stored outdoors, does not create a
condition of exposure, provided the
materials/products are adequately protected from
storm water and do not have the potential to be
released as a result of a leak or spill.
Order 2014-0057-DWQ
e. Final products built and intended for use outdoors
(e.g., new cars), provided the final products have
not deteriorated, are not contaminated, or are not
otherwise potential sources of contaminants.
Types of final products not qualifying for a
certification of “No Exposure”:
i. Products that may be mobilized in storm water
discharges (e.g., rock salt).
ii. Products, which may, when exposed, oxidize,
deteriorate, leak, or otherwise be a potential
source of contaminants (e.g., junk cars,
stockpiled train rails).
iii. “Final” products that are, in actuality,
“intermediate” products. Intermediate products
are those used in the composition of yet another
product (i.e., sheet metal, tubing, and paint used
in making tractors).
iv. Even if the intermediate product is “final” for a
manufacturer and destined for incorporation in a
“final product intended for use outdoors,” the
product is not allowed to be exposed because
they may be chemically treated or are
insufficiently impervious to weathering.
f. Special Conditions for Construction Activities
Permanent, uninterrupted sheltering of industrial
activities or materials may not always be possible
during facility renovation or construction. When such
circumstances exist, the Discharger is not required to
obtain coverage under an NPDES permit as long as the
following conditions are met:
i. Materials and activities are protected with
temporary covers or shelters (i.e. tarpaulins);
ii. Temporary covers or shelters prevent the contact
of storm water to materials and activities;
iii. Materials are subject to wind dispersion are not
stored under temporary sheltering;
iv. Temporary shelters are only used when
necessary during facility renovation or
construction and until permanent storm-resistant
shelters as described above are available; and,
v. Temporary shelters are only used for a single
period of ninety days or less. (Facilities with
construction and renovation projects that will
need the use of temporary shelters beyond 90
days, or that will require multiple periods of ninety
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