Peroxide forming chemicals: controlling the hazard
Over the last few years, HSE has received numerous requests for assistance with expired peroxide forming chemicals. Bottles are often in poor condition, with evidence of chemical precipitate, crystallization, and phase separation. Peroxide crystals may explode on contact, presenting a serious risk of injury to people and property. Incidents involving shock-sensitive peroxides have occurred at other post-secondary institutions, including Berkeley, the University of Minnesota, and the University of California San Francisco.
Which chemicals form peroxides?
Peroxide forming chemicals are common in research laboratories and include ethers, alkenes, and secondary alcohols. To determine if you have peroxide formers in your lab, review this list of common peroxide forming chemicals and consult the safety data sheet for each chemical you will be handling. Be alert for chemicals (like tetrahydrofuran) that contain oxidation inhibitors — these are used to slow the formation of peroxides and deplete over time, leaving behind an uninhibited peroxide former with the potential to form shock-sensitive crystals.
What should you do with expired peroxide formers?
Disposal of expired peroxide formers is a high-risk process. If a bottle of peroxide forming chemicals shows signs of phase separation, precipitate, or crystallization and/or is undated or more than two years old, do not open or move the bottle. Instead, post a warning sign nearby to prevent anyone from handling the chemical and contact HSE immediately at hse.info@ualberta.ca. Health, Safety and Environment will examine the bottle and take the necessary steps to eliminate the hazard safely.
Remember: never open a container where peroxide crystals are evident or suspected; even twisting the cap to open a bottle may lead to an explosion.
Implementing controls
Safe handling and disposal of peroxide formers is key to reducing the hazard associated with these chemicals. Review the Chemical Storage Guidelines and Peroxide Forming Chemicals Program and adhere to recommended safety practices. Label bottles of peroxide formers with the dates they were received, opened, and when they should be disposed of through Chematix — no more than two years after the date of receipt. Note this in your inventory as well so that expired bottles aren’t forgotten. Limiting purchases of peroxide formers, regular inventory monitoring, and accurate labeling are critical hazard control measures for these chemicals.
For more information contact HSE at hse.info@ualberta.ca
