Process Safety Information

Employers must complete a compilation of written process safety information before conducting a process hazard analysis or evaluation. The compilation of written process safety information is useful in identifying and understanding the hazards posed by processes that involve acutely hazardous chemicals. The written process safety information includes information on the hazards of the chemicals used in the process, the technology of the process, and the necessary process equipment.

Information on the hazards of the chemicals used in the process must include at least the following:

• Toxicity
• Permissible exposure limits
• Physical data
• Reactivity data
• Corrosivity data
• Thermal and chemical stability data
• Hazardous effects of the inadvertent mixing of different materials

Information on the technology of the process must include at least the following:

• Block flow diagram or simplified process flow diagram
• Process chemistry
• Maximum intended inventory
• Safe upper and lower limits for temperatures, pressures, flows, or compositions
• Evaluation of the consequences of deviations

Where the original technical information no longer exists, employers must develop the information in conjunction with the process hazard analysis, and include enough detail to support the analysis.

Information on the equipment in the process must include at least the following:

• Construction materials
• Piping and instrument diagrams (P&IDs₁)
• Electrical classification
• Relief system design and design basis
• Ventilation system design
• Design codes and the standards that are being employed
• Material and energy balances for processes built after September 1, 1992
• Safety systems (such as interlocks, detection and suppression systems, and so forth)
• Electrical supply and distribution systems

Sometimes existing equipment has been designed and constructed in accordance with codes, standards, or practices that are no longer in general use. In these situations, the employer shall determine and document that the equipment is being maintained, inspected, tested, and operated in a safe manner.

The compilation of the listed process safety information provides the basis for identifying and understanding the hazards of a process, and is necessary in developing the process hazard analysis. A copy of the process safety information and communication must be accessible to all employees who perform duties in or near the process.

To learn more about Process Safety Management visit our Cal/OSHA Process Safety Management Online Training web page.