Pre-Startup Safety Review: A Practical Guide

By the Aetso Technical engineering team · Reviewed November 2026 · 6 min read

Startup is one of the most hazardous periods in the life of a process. Equipment is new or newly modified, procedures may be untested, and people are doing unfamiliar tasks. The pre-startup safety review (PSSR) is the final check that a facility is ready before highly hazardous chemicals are introduced.

When a PSSR is required

Under OSHA PSM (29 CFR 1910.119(i)), a PSSR is required for new facilities and for modified facilities when the modification is significant enough to require a change in the process safety information. EPA RMP Program 3 contains the same requirement. Many companies also apply PSSRs to restarts after major turnarounds or extended shutdowns.

What the PSSR must confirm

Before hazardous chemicals are introduced, the review must confirm that:

• Construction and equipment are in accordance with design specifications.
• Safety, operating, maintenance and emergency procedures are in place and adequate.
• For new facilities, a PHA has been performed and its recommendations resolved or implemented before startup.
• Modified facilities meet the requirements of management of change.
• Training of each employee involved in operating the process has been completed.

Making the PSSR meaningful

• Walk the field. A PSSR conducted only in a conference room cannot confirm that construction matches the design.
• Use a scaled checklist. Tailor the checklist to the scope of the change; a generic list invites box-ticking.
• Involve operators. Those who will start up the unit are best placed to judge readiness.
• Classify open items. Distinguish items that must be closed before startup from those that can follow with a documented plan.
• Verify safeguards. Confirm relief devices are installed and unblocked, interlocks are tested and bypasses are removed.
• Close the loop. Track post-startup items to completion.

Common PSSR findings

• P&IDs not updated to as-built condition
• Car-sealed valves in the wrong position or without seals
• Safety instrumented functions not validated
• Procedures not revised for the change, or not yet trained
• Temporary construction equipment left in place