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OSHA Issues Revised Memorandum on PSM of Highly Hazardous Chemicals and Covered Concentrations

July 22, 2016

REGULATORY ADVISORY--On July 18, the Occupational Safety and Health Administration (OSHA) released a revised memorandum regarding highly hazardous chemicals and their covered concentrations, which has rescinded and replaced the original June 5, 2015 memorandum. Read the detailed memorandum on OSHA's website.

The revised memorandum provides better clarity for determining the quantity of a highly hazardous chemical (HHC) in a process, and thus whether the process contains an HHC quantity above the threshold limits listed in Appendix A of 29CFR 1910.119. In general, the revised memorandum specifies that one should calculate the weight of the HHC present in the process using a method similar to the approach used by the Environmental Protection Agency (EPA) in the Clean Air Act Amendment.

Additional information is provided in the memorandum regarding implementation of Process Safety Management for processes that are now "covered" according to the memorandum requirements. 

Learn more about US regulatory reforms for process safety.


About ABS Group

ABS Group of Companies, Inc. (, through its operating subsidiaries, provides technical advisory and certification services to support the safety and reliability of high-performance assets and operations in the oil, gas and chemical, power generation, marine, offshore and government sectors, among others. Headquartered in Houston, Texas, ABS Group operates with more than 1,000 professionals globally. ABS Group is a subsidiary of ABS (, a leading marine and offshore classification society.

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