Process Safety Management of Highly Hazardous Chemicals is the OSHA standard that aims to prevent catastrophic releases of toxic, reactive, flammable or explosive chemicals. It requires covered facilities to manage the hazards of their processes through a set of linked elements, from process hazard analysis and written operating procedures to mechanical integrity, management of change and incident investigation.
The rule protects employees and, indirectly, surrounding communities from fires, explosions and toxic releases. It applies to refineries, chemical plants and many facilities that would not call themselves chemical companies, such as ammonia refrigeration operations, water treatment plants using chlorine, and sites that store large quantities of flammable liquids or gases.
What Is the Process Safety Management Standard?
PSM is codified at 29 CFR 1910.119, in Subpart H (Hazardous Materials) of the general industry rules. OSHA issued it in 1992. Construction work on covered processes is addressed at 1926.64, which mirrors the general industry text. The EPA's Risk Management Program (40 CFR Part 68) covers many of the same facilities with a parallel prevention program focused on off-site consequences.
Key definitions in 1910.119(b):
- Process: any activity involving a highly hazardous chemical, including use, storage, manufacturing, handling or on-site movement. Interconnected vessels, and separate vessels located so that a release could involve them, count as a single process.
- Highly hazardous chemical: a substance with toxic, reactive, flammable or explosive properties as specified in the applicability paragraph.
- Catastrophic release: a major uncontrolled emission, fire or explosion involving one or more highly hazardous chemicals that presents serious danger to employees in the workplace.
See also the glossary entry on process safety management.
Who Must Comply?
Under 1910.119(a)(1), the standard applies to:
- A process involving a chemical listed in Appendix A at or above its threshold quantity. Thresholds vary by chemical.
- A process involving 10,000 pounds or more of a Category 1 flammable gas or a flammable liquid with a flashpoint below 100°F on site in one location.
The flammables trigger does not include hydrocarbon fuels used solely for workplace consumption as a fuel, such as propane for comfort heating, unless the fuel is part of a process containing another highly hazardous chemical. It also excludes flammable liquids stored in atmospheric tanks or transferred while kept below their normal boiling point without the benefit of chilling or refrigeration.
Under 1910.119(a)(2), the standard does not apply to retail facilities, oil or gas well drilling or servicing operations, or normally unoccupied remote facilities. State Plan states enforce their own process safety rules, which must be at least as effective as the federal standard and may go further.
Key Requirements: The PSM Elements
Employee participation, (c)
Employers must have a written plan for employee participation, consult employees and their representatives on hazard analyses and other elements, and give them access to process hazard analyses and other PSM information.
Process safety information, (d)
Before conducting a process hazard analysis, the employer must compile information on the hazards of the chemicals, the process technology (flow diagrams, chemistry, maximum intended inventory, safe upper and lower limits and the consequences of deviation) and the equipment (materials of construction, piping and instrument diagrams, electrical classification, relief system design and safety systems). The employer must document that equipment complies with recognized and generally accepted good engineering practices.
Process hazard analysis, (e)
The PHA identifies, evaluates and controls the hazards of the process using an appropriate method such as What-If, Checklist, HAZOP, FMEA or fault tree analysis. It must address previous incidents with catastrophic potential, engineering and administrative controls, facility siting and human factors. The team needs engineering and process operations expertise, at least one employee with experience in the process, and one member knowledgeable in the methodology. Recommendations must be resolved promptly and documented. PHAs must be updated and revalidated at least every five years and retained for the life of the process.
Operating procedures, (f)
Written procedures must cover each operating phase, including initial startup, normal operations, temporary operations, emergency shutdown, emergency operations, normal shutdown and startup after a turnaround or emergency shutdown. They must also cover operating limits, safety and health considerations and safety systems. The employer must certify annually that procedures are current and accurate, and develop safe work practices for activities such as lockout/tagout, confined space entry and opening process equipment.
Contractors, (h)
Host employers must evaluate a contractor's safety performance before selecting it, inform contractors of process hazards and the emergency action plan, control their entry, periodically evaluate their performance and keep a log of contract employee injuries and illnesses related to work in process areas. Contract employers must train their workers and document that training.
Pre-startup safety review, (i)
New facilities and modified facilities where the change requires an update to process safety information must complete a review before highly hazardous chemicals are introduced, confirming construction matches design, procedures are in place, PHA recommendations or MOC requirements are addressed and employees are trained.
Mechanical integrity, (j)
Pressure vessels and storage tanks, piping systems, relief and vent systems, emergency shutdown systems, controls and pumps must have written maintenance procedures, trained maintenance personnel, inspection and testing that follows good engineering practice, documented results, and timely correction of deficiencies. New equipment and spare parts must be suitable for the process application.
Hot work, (k)
A hot work permit is required for hot work on or near covered processes. It documents the fire prevention and protection requirements of 1910.252(a), the authorized dates and the object of the work, and is kept on file until the work is complete.
Management of change, (l)
Written procedures must manage changes, other than replacement in kind, to process chemicals, technology, equipment, procedures and facilities. Before a change, the employer must address its technical basis, impact on safety and health, needed procedure changes, time period and authorization requirements. Affected employees must then be informed and trained, and process safety information and procedures updated. See the glossary entry on management of change.
Incident investigation, (m)
Every incident that resulted in, or could reasonably have resulted in, a catastrophic release must be investigated, starting no later than 48 hours after the incident. The report covers dates, a description, contributing factors and recommendations, findings must be resolved and documented, and reports must be kept for five years.
Emergency planning, (n)
Employers must establish an emergency action plan for the entire plant under 1910.38, including procedures for handling small releases.
Training, Audits and Records
- Initial training, (g)(1): Each employee involved in operating a process must be trained in an overview of the process and the operating procedures, with emphasis on hazards, emergency operations and safe work practices.
- Refresher training, (g)(2): At least every three years, and more often if necessary, with frequency set in consultation with employees.
- Training records, (g)(3): Identity of the employee, date of training and the means used to verify understanding.
- Compliance audits, (o): Certify compliance at least every three years, document responses to findings, and keep the two most recent audit reports.
- Retention: PHAs and their updates for the life of the process. Incident investigation reports for five years.
Common Compliance Mistakes
- Missing that a process inventory crosses a threshold quantity.
- PHA recommendations left open for years without documented resolution.
- Operating procedures that do not match how the unit is actually run, or no annual certification.
- Mechanical integrity inspections that are overdue or not documented.
- Changes made through work orders that bypass management of change.
- Compliance audits that skip elements or produce findings that are never closed.
For current maximum OSHA penalty amounts, see OSHA's penalties page. OSHA's latest regulatory agenda lists a PSM update as a long-term action, so the 1992 rule remains the current requirement.
How to Comply: Step by Step
- Determine applicability. Compare maximum intended inventories against Appendix A thresholds and the 10,000-pound flammables trigger.
- Define process boundaries. Identify interconnected vessels and nearby equipment that make up each covered process.
- Compile process safety information. Gather chemical, technology and equipment data and close any gaps.
- Conduct the PHA. Assemble a qualified team, choose a method, and track every recommendation to closure.
- Write and certify procedures. Cover every operating phase and certify them annually.
- Train and document. Deliver initial training and refreshers at least every three years.
- Build mechanical integrity and MOC programs. Schedule inspections and route every non-in-kind change through MOC.
- Investigate, audit and improve. Investigate incidents within 48 hours and audit all elements at least every three years.
How SMS360 Helps
The SMS360 Management of Change module gives facilities a structured workflow for proposing, reviewing, approving and closing changes, with digital forms that capture the technical basis, safety impact and required training, and a record of each approval.
Across the wider platform, teams can track PHA and audit recommendations as corrective actions, store procedures and process safety information in a document library, keep training records with reminders for three-year refreshers, and use dashboards to see overdue items across the PSM program.
Frequently Asked Questions
What is the threshold quantity for OSHA PSM?
It depends on the chemical. Appendix A of 1910.119 lists toxic and reactive chemicals with individual threshold quantities. For flammable gases and flammable liquids with a flashpoint below 100°F, the threshold is 10,000 pounds on site in one location, subject to the fuel and atmospheric storage exclusions.
How often must a process hazard analysis be revalidated?
At least every five years. The update must be done by a team meeting the standard's requirements so the PHA stays consistent with the current process. PHAs and their updates must be kept for the life of the process.
What are the 14 elements of PSM?
They are commonly listed as employee participation, process safety information, process hazard analysis, operating procedures, training, contractors, pre-startup safety review, mechanical integrity, hot work permit, management of change, incident investigation, emergency planning and response, compliance audits and trade secrets. They correspond to paragraphs (c) through (p) of 1910.119.
Is PSM the same as EPA's Risk Management Program?
No, but they overlap. OSHA PSM protects workers and is enforced by OSHA, while EPA's RMP rule focuses on preventing releases that affect the public and the environment. Many facilities are covered by both, and RMP's Program 3 prevention program closely tracks the PSM elements.
