Faxback 11115

9441.1985(42)

DEC 13 1985

MEMORANDUM

SUBJECT: Regulatory Interpretation for Pesticide Applicator
Washing Rinse Water

FROM: Marcia E. Williams, Director
Office of Solid Waste

TO: Harry Seraydarian, Director
Toxics and Waste Management Division
EPA Region IX

This is in response to your memorandum dated September 16,
1985, regarding the regulatory status of washwaters that are
generated by washing the exterior of a pesticide serial
applicator's airplane. You expressed concern that the
interpretation set forth in our July 22 memorandum does not
consider the ultimate disposal and the hazard presented by
these washwaters and the enforcement problems that such an
interpretation would cause. In particular, in the study that
was submitted with your memo, that data appear to suggest that
there is a potential for migration of pesticide residues resulting
in contamination of ground water. Therefore, you request that
we re-visit this issue. In addition, you also request that we
expedite the regulations designed to close the current loop-hole
concerning mixtures of spent solvents and other commercial
products.

Although I understand your concerns and generally agree
with you that these rinse waters may present a hazard if they
are not properly managed, I must agree with Dr. Skinner in this
interpretation of the rules; any other reading of the rules
would argue that any chemical that is released into the environ-
ment as a result of use would be disposed and regulated under
RCRA. In particular, the mixture rule states that if a solid
waste and a hazardous waste are mixed, the entire mixture is
defined as hazardous. At issue here is whether the pesticide
that adheres to the exterior of the airplane is defined as a
"RCRA hazardous waste." To be defined as a RCRA hazardous


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waste, the pesticide would have to be an unused discarded
commercial chemical product. See 40 CFR §261.33. Since
the pesticide has been sprayed from the airplane, it technically
has been used and, therefore, is not defined as a §261.33 commercial
chemical product. (On the other had, the pesticide residue
that remains in the spray tanks after the spraying operation
has not technically been used and, thus, would be defined as
a §261.33 commercial chemical product.) Any other inter-
pretation would go beyond the intent of RCRA and the implementing
regulations. These pesticide washwaters, therefore, are not
defined as hazardous because of the mixture rule.

Nevertheless, it should be noted that the interpretation
should not be taken to mean that we have evaluated these wastes
and have determined that they are non-hazardous. As I already
indicated, these washwaters may be hazardous (as evidenced by
the study you attached with your memo) and may present as much
of a hazard as the rinsate from spray tanks (which are currently
subject to regulation). In fact, we have begun a study to
try to define the levels at which these washwaters may present
a hazard if these washwaters are mismanaged (i.e., placed in
unlined surface impoundments). The study is expected to be
completed (at least as a draft) by the end of this year and we
will keep you apprised of the results. Based on the date, as
well as any other information that is collected, we may take
further action to control these washwaters.

With respect to your other request to close the current
loop-hole concerning solvent mixtures and other commercial
products, the solvent mixture rule is expected to be promulgated
in December, while the commercial chemical product mixture
rule is expected to be proposed very shortly.

Please feel free to call Matt Straus if you have any
questions or comments; his telephone number is (8) 475-8551.

cc: A&WM Division Directors (Regions I-VIII and X)
S. Shatzow