Secondary containment for cyanide electroplating baths

November 9, 1983

Robert H. Elliott, Jr.
[Recipient address omitted]
Dear Mr. Elliott:

This letter was prepared in response to your written inquiry (copy attached of October 28, 1983 regarding cyanide electroplating baths. You questioned the need for diking around the tank in cases where there are dual concentric tanks; i.e., a tank within a tank. In the latter case leakage of cyanide from the inner tank would appear in a sight glass in the outer tank and/or sound an alarm at some predetermined level of leakage. You also questioned whether it is necessary to separate rinse streams.

As you are aware, the hazard from cyanide is primarily toxicity and not fire or explosion for which regulation by the Flammable and Combustible Liquid standard, 29 CFR 1910.106, is intended. Diking or drainage requirements pertain to this standard.

It appears, therefore, that your approach to handling tank cyanide leakage is satisfactory to OSHA. Also, we have no requirement for separating rinse streams. If you have additional questions please contact the Technical Support Group of this office.

Thank you for your interest in occupational safety and health.

Sincerely yours,

LINDA R. ANKU
Regional Administrator