Ask the Expert Question-and-Answer Archive (TRI)

by Joelie Zak, Scientific Control Labs, Inc.
April, 2004

Flux material - processed or otherwise used?

Q. During a recent EPA inspection we were pointed out that our use of 25,000-lb threshold for flux material (usually a zinc ammonium chloride used in wet zinc galvanizing process) was WRONG. The inspector told us that in the EPAs opinion the flux is being "otherwise used" and, therefore, we should use the 10,000-lb threshold. We disagree with this opinion. Could you help us to identify which threshold is the CORRECT one to use when considering usage of flux in a hot dip zinc galvanizing process. In our case, flux is added directly to the molten zinc kettle where it floats atop the molten zinc. A steel part passes through the flux with intent to remove oxides and to prevent oxidation prior to submerging it into the molten zinc bath. In the industry, it is also referred to as "flux inclusion". Thank you for your help!

A. In the Form R instructions, one category definition of "otherwise use" is summarized as: "Otherwise Use of the TRI Chemical: a) As a chemical processing aid, not intended to remain in or become part of the product, such as solvents, inhibitors, caylysits, intiatiors, reaction terminators. In the metal finishing industry, it is generally interpreted that unless if doesnt remain as a deposit on the part, it is otherwise used. For example, solvents used for cleaning, acids used for pre-dipping, and even cyanide in a plating bath are all considered otherwise used TRI chemicals. Because the flux is intended to be used to remove oxides & prevent oxidation vs. not to actually deposit the zinc, Im afraid that the 10,000 lb. threshold for "Zinc Compounds" would apply.