pec

6 Potentially Explosive Chemicals B. Common Laboratory PECs Potentially Explosive Chemicals (PECS) are used in academic research and teaching laboratories. Examples include: • Organic chemicals that form peroxides through exposure to air or light • Hydrated picric acid or other tri-nitro and di-nitro compounds that become dry or become contaminated with metals that form explosive metal salts • Sodium amide that reacts with air or moisture to form superoxides, as evidenced by yellow or brown discoloration • Certain alkyl nitrates (e.g., butyl nitrate or propyl nitrate) that become contaminated with nitrogen oxides • Certain normally stable perchlorates (e.g., pyridium perchlorate or tetraethylammonium perchlorate) that become unstable at elevated temperatures Contact ISU Environmental Health and Safety (EH&S) at (515) 294- 5359 or Ames Laboratory Environment, Safety, Health (ESH) at (515) 294-2153 immediately if you suspect a material is an outdated PEC. Post warning signs so others do not handle or disturb the material. Safety office personnel will inspect the chemical and devise an appropriate action plan that ensures safe disposal. NOTE: Use extreme caution before concentrating or purifying any mixture that may contain an explosive chemical (e.g., a peroxide forming chemical or perchlorate). NOTE: There is a great deal of uncertainty regarding the hazards and safe handling of PECs. For example, with peroxide forming chemicals, there are no definite data available about the concentration and specific conditions at which these peroxides will detonate. Several common test methods may not detect all types of unstable peroxides. Deperoxidation procedures may not remove all types of unstable peroxides. Also, there are no specific federal or state OSHA regulations on this subject It is paramount that researchers be aware of the hazards associated with PECs.