9441.1991(03)

United States Environmental Protection Agency
Office of Solid Waste and Emergency Response
Washington, D.C. 20460

March 19, 1991

Melanie K. Pierson
Assistant U.S. Attorney
U.S. Department of Justice
Southern District of California
United States Courthouse
940 Front Street, Room 5-N-19
San Diego, California  92189

Dear Ms. Pierson:

     This responds to your February 26, 1991 letter to Ms. Becky
Cuthbertson regarding the regulatory status of solder dross
generated by the periodic skimming of molten solder baths used in
the production of printed circuit boards to remove contaminants
acquired through use of the molten solder baths.  Your specific
question concerns whether this solder dross meets the description
of a "by-product" or a "spent material" in the context of the
hazardous waste regulations.

     Although it is not specifically defined, the term "dross" is
used as an example of a by-product in the January 4, 1985 Federal
Register preamble to the current definition of solid waste (see
50 FR 625).  Further, there is an example in EPA's "Guidance
Manual on the RCRA Regulation of Recycled Hazardous Wastes"
(March, 1986) in which solder drosses generated in soldering
integrated circuits to printed circuit boards are determined to
not be solid wastes because they are identified as
"characteristic by-products that are reclaimed."

     Typically, a "dross" is generated prior to using a metal or
alloy by melting the metal or alloy and skimming off the
contaminants and oxides that have developed since the metal or
alloy was refined.  In the soldering of integrated circuits to
printed circuit boards (as in the example given in the guidance
manual), the dross is generated as a by-product (of the solder)
when the solder is melted during its use.  However, although the
generator may claim that a secondary material is a "dross" (and
the material may, in fact, appear to be a "dross"), that does not
automatically mean that the material is a by-product rather than
a spent material.

     The determining consideration in classifying a secondary
materials is how the material is generated, not the term used to
describe it (e.g., "dross").  As a product that has been used in
the process, the solder skimmings, when removed (i.e., skimmed
off) from the process due to contamination of the molten solder
bath during its use in the process, would more clearly meet the
definition of a spent material than a by-product.  Rather than
being a by-product of the solder itself, the skimmings are spent
materials from the use of the solder.

     As you know, this regulatory interpretation reflects the
Federal program.  You should also contact the appropriate State
regulatory agency to determine the regulatory status of the
solder dross under their program.

     I hope this has helped to answer your questions.  Should you
have any further questions, you can contact Mr. Mitch Kidwell, of
my staff, at (202) 475-8551, or Ms. Jeannie Paige, of the EPA
Region IX office, at (415) 744-2073.

Sincerely,

David Bussard
Director
Characterization and Assessment Division

cc:  Jeannie Paige