Incident due to ineffective PSM system

 OSHA's inspection identified several serious deficiencies in a company's process safety management program, a detailed set of requirements and procedures employers must follow to proactively address hazards associated with processes and equipment that involve large amounts of hazardous chemicals. In this case, the chemical was acetone, used in a PSM-covered process known as direct solvation. On the day of the explosion, a valve on a transfer line inadvertently was left open, resulting in the release of flammable acetone vapors. The vapors exploded after being ignited by an undetermined source.

"In this case, the company knew from prior third party and internal compliance audits conducted at the plant that aspects of its PSM program were incomplete or inadequate, and misclassified electrical equipment was in use. The company did not take adequate steps to address those conditions,"

"Luckily, the explosion happened when there were few workers in the plant. Otherwise, this incident could have resulted in a catastrophic loss of life."

Specifically, OSHA found that the process safety information for the solvation process was incomplete. The employer's analysis of hazards related to the process did not address previous incidents with a potential for catastrophic results, such as forklifts that struck process equipment, and did not address human factors such as operator error, communication between shift changes and employee fatigue from excessive overtime. In addition, the company did not ensure that a forklift and electrical equipment, such as a light fixture, switches and a motor, were approved for use in Class 1 hazardous locations where flammable gases or vapors are present. 

Source:OSHA.gov