OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

November 9, 1983

Robert H. Elliott, Jr.
6027 Cannon Hill Road
Fort Washington, PA 19034

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,

Regional Administrator