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.

JAN 31 1991



SUBJECT:          Interpretation of 29 CFR 1910.109 Relative to
                 Peroxides and Chlorates in Blasting Agents, 
                 Slurries, and Emulsions

This is in response to your memorandum of November 14, attaching a request for interpretation of 29 CFR 1910.109 for Mr. John C. Orth.

The Occupational Safety and Health Administration (OSHA) does not approve or certify end products.

We will answer the questions in the order that they were presented. First, does 29 CFR 1910.109(h)(3)(iii)(e) apply to ammonium nitrate based emulsion type blasting agents and explosives? Yes, 29 CFR 1910.109(h) applies to these blasting agents, water gel (slurry), and emulsion type explosive materials.

Second, regarding the prohibition of peroxides and chlorates in blasting agents, 29 CFR 1910.109(h)(3)(iii)(e) prohibits peroxides and chlorates as part of the oxidizer system of these materials.

Third, what percent concentration of peroxide chlorate is permissible in water gel-slurry explosives and blasting agents, if not part of the oxidizer system? OSHA has no specific permissible concentration of peroxide or chlorate in water gel- slurry explosives and blasting agents not part of the oxidizer system.

Fourth, is it permissible to add small amounts of peroxides or chlorates to blasting agents, if they decompose harmlessly within a short period of time? No, 29 CFR 1910.109(h)(3)(iii)(e) prohibits any addition or use of peroxides or chlorates. How long a decomposition time would be acceptable? OSHA has not set a decomposition time limit.

Fifth, is it permissible to use in water gel blasting agents or explosives small amounts of chemicals which may be peroxide or chlorate at some time...? 29 CFR 1910.109(h)(3)(iii)(e) again prohibits the use of peroxides or chlorates in blasting agents and explosive materials.


GICA:SAA:LPolito:tf:12-13-90:file #saa.62l corliss comp. dcp#1922 cc:Clark,Donnelly,Stroup,Polito,HRT,OTI,OCIS,CHRON