9441.1991(18)

OFFICE OF SOLID WASTE AND EMERGENCY RESPONSE

DEC 9 1991

Mr. James C. Brown
c/o American Electronics Association
1225 Eye St., N.W., Suite 950
Washington, D.C.  20005

Dear Mr. Brown:

Thank you for your letter of October 2, 1991, describing
your concerns about our recent interpretation of Resource 
Conservation and Recovery Act (RCRA) regulations that apply to 
solder dross generated in manufacturing printed circuit boards.

To briefly restate the issue, you are concerned about a 
March 19, 1991 letter from David Bussard that classifies solder
"dross" generated by the use of solder in printed circuit board 
manufacturing as a spent material under the RCRA hazardous waste 
regulations (and thus, as a solid and hazardous waste).  The
March 19 letter was based upon the information that we had at the 
time, and differentiates between spent materials and by-products.
As you noted in our October 16 meeting, previous EPA statements 
about the status of solder dross and solder skimmings from
printed circuit board manufacturing were that skimmings and
drosses are by-products - and thus are not solid or hazardous
wastes when reclaimed, under the federal RCRA regulations (40 CFR 
261.2).

The term "dross" is frequently used by industry to refer to
an oxide layer that forms on the surface of molten metal,
regardless of whether the metal is a virgin metal being reshaped 
into a different form, or is a metal in use (such as solder). 
Previous statements, and an example in the January 4, 1985
Federal Register preamble, have generally referred to "drosses"
as by-products under the RCRA hazardous waste regulations.
Although some drosses are by-products under federal rules, the 
language of the regulations and the circumstances of a material's 
use, including whether the material becomes contaminated,

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determine how it is classified.  For example, when circuit board
manufacturers have to change their solder baths due to 
contamination, the material removed from the bath is a spent 
material.

It appears that our imprecise use of the term "dross" and 
previous statements that solder skimmings or drosses are "by-
products" may have led to widespread practices in the electronics
manufacturing industries, where the skimmings have been managed
as if they were by-products (and thus, neither solid nor
hazardous wastes when reclaimed).

We think it is important to obtain additional information.
We are currently in the process of gathering information to 
determine how the solder drosses or skimmings generated in
printed circuit board manufacturing should be regulated, if at
all, under RCRA Subtitle C.  That information will include the 
levels of contamination in dross and skimmings as solders are
used in circuit board manufacturing as well as a broader look at 
information bearing upon the handling of dross and skimmings
after removal from the solder bath.  The information, as well as
the issues raised about classifying dross in the future under
RCRA, are also relevant in the broader context of revisions to
the definition of solid waste.  We hope to publish an Advance
Notice of Proposed Rulemaking discussing these revisions by the
end of the year, to engage public debate on these important 
questions.  Many of the issues you raised in your October 2
letter are part of larger questions, such as whether to use the 
regulations as a tool to encourage safely conducted resource 
recovery.

Therefore, until we have gathered more data on the
industry's practices (both at generator sites and recycling 
facilities), we will continue to treat solder drosses generated
from soldering printed circuit boards as by-products, rather than
as spent materials.  As a result, solder drosses from printed 
circuit board manufacturing that are reclaimed would not have to
be managed as solid or hazardous wastes under RCRA regulations
(40 CFR 261.2).  Please note that this letter relates only to the 
federal hazardous waste regulations.  States may have
requirements that are more stringent or broader in scope; thus,
you would need to contact individual states to determine their 
requirements in a specific situation.

With respect to the particular solder drosses in question,
this letter is based on specific factual circumstances, including 
your reliance on prior Agency statements.  Thus, this letter has
no application to other industries or materials.

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Thank you once again for your interest in this matter.  If 
you have further questions please contact David Bussard of my 
staff at (202) 260-4637.

Sincerely yours,

Original Document signed

Don R. Clay
Assistant Administrator