Answer Library / Process Safety OSHA letter · 2019-09-20

Does the 5-year PHA revalidation clock pause during an extended plant shutdown?

Quick answer

No. The five-year Process Hazard Analysis revalidation cycle cannot be delayed or restarted just because a plant or process unit is shut down (29 CFR 1910.119(e)(6)). However, OSHA will not require a PHA while the process is fully de-inventoried and purged of highly hazardous chemicals; if the deadline passes during shutdown, the PHA must be updated before hazardous chemicals are reintroduced.

A Houston-based inquirer asked whether the PSM requirement to update or revalidate a Process Hazard Analysis at least every five years can be delayed and restarted after a facility has been shut down for an extended period. OSHA answered no: the five-year cycle "cannot be delayed or applied retroactively while a plant or process unit within a chemical facility is shutdown." The clock runs as a fixed timeline from completion of the prior analysis; a PHA completed January 1, 2020 must be updated by January 1, 2025 regardless of shutdown status.

OSHA did offer practical relief: it will not mandate a PHA during periods when the covered process is fully de-inventoried and purged of all highly hazardous chemicals. If the five-year deadline passes before restart, the employer simply must update the PHA before reintroducing hazardous chemicals into the process.

OSHA also listed what else must happen before restart: management of change documentation for any non-replacement process modifications (29 CFR 1910.119(l)), updates to process safety information and operating procedures, an assessment of personnel training including refresher requirements (29 CFR 1910.119(g)(2)), review of prior incident investigations and compliance audits, and a pre-startup safety review under 29 CFR 1910.119(i)(1) and (i)(2).

29 CFR 1910.119(e)(6)29 CFR 1910.119(l)29 CFR 1910.119(g)(2)29 CFR 1910.119(i)(1)29 CFR 1910.119(i)(2)
Source: OSHA Standard Interpretation letter, 2019-09-20 — read the official letter on osha.gov →
Interpretation letters explain how OSHA applies its rules to specific situations. Always verify current requirements — regulations and enforcement policies change.

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