Common Audit Findings 4 – Process Safety Information and Process Hazard Analysis Issues

Hazardous Effects of Inadvertent Mixing: Facilities often rely on the “Incompatibilities” (or similar) sections in the SDSs for the hazardous effects of inadvertent mixing, but SDSs rarely address the specific chemicals present in a process or only address the incompatible types of chemicals (e.g., bases, oxidizers) that may not be specific or well understood by the operators. Industry typically provides and references a Chemical Interaction Matrix (or similar) [6, 8] that shows all the process chemicals (and possibly materials of construction) and notes the hazards involved with each possible specific interaction within the boundaries of the process.  The Chemical Reactivity Worksheet is a free tool for evaluating chemical and material interactions [8].

Maximum Intended Inventory: Common issues are (1) there is an inventory (or inventories) but the basis is not documented, (2) the inventory is not consistent with that reported in the facility’s latest risk management plan (RMPlan), and (3) the inventory does not appear to include process piping and smaller equipment inventories and/or it has not accounted for onsite inventories of railcars, trucks, or containers (an EPA RMP requirement). GIP is to (1) document (e.g., via spreadsheets) details of the maximum inventory for each covered chemical in storage tanks, major equipment, and onsite storage and (2) include (or estimate) a reasonable amount (typically at least 10%) to account for piping and smaller equipment. Plants should document any differences between the maximum intended inventories and RMPlan inventories for consistency during PSM audits and RMPlan resubmissions.

Relief System Design: Available relief device calculations often lack documentation of all overpressure cases (e.g., design basis case and alternatives), inlet pressure drop, outlet pressure drop, reactive forces, and/or venting to a “safe” location. API 521 [11] provides guidance for developing and documenting relief device data.  Failure to provide complete data for the relief system design and design basis has resulted in many OSHA citations.  Ensuring a facility has complete and up-to-date relief system design information typically involves (1) surveying to determine whether calculations exist for all the relief devices (including relief valves, rupture disks, conservation vents, and emergency vents), (2) assessing each calculation to ensure it meets API 521 or other appropriate requirements, and (3) updating the calculations, as necessary.

Material and Energy Balances: The most common issues are that the balances have not been updated on (1) capacity/throughput increases, (2) manufacturing recipe changes, or (3) new chemicals additions. Also, simple or batch processes frequently have no documented balances. These can be addressed by (1) ensuring the MOC program reviews the balances for appropriate changes and (2) developing actual or representative balances for simple/batch processes.

Lists of Incidents, MOCs, and Previous PHA Recommendations: The regulations require PHAs to identify and review previous incidents (with catastrophic potential) and GIP also includes review (1) of MOCs completed (unless a complete “redo” revalidation is performed) and (2) if the previous PHA recommendations were adequately completed and sustained. Typically, lists of each of these items are developed and then reviewed by the PHA team.  However, (1) these lists are often not documented, (2) the PHA team fails to evaluate them adequately and include any required changes to the PHA worksheets, or (3) the current team does not adequately evaluate whether the recommendations were implemented and were adequate.  These issues can be addressed by (1) evaluating all these items and (2) adding a column to the lists that documents whether there was an impact on the PHA worksheets (e.g., adding a new deviation from an incident or a new safeguard from an MOC or PHA recommendation that was implemented).

Detection Methodologies: Toxic and/or combustible gas detectors are included in (1) the safety systems in the PSI and operating procedures elements, (2) the PHA element, and (3) the mechanical integrity element (i.e., monitoring devices).  The PHA requirement is to address “Engineering and administrative controls applicable to the hazards and their interrelationships such as appropriate application of detection methodologies to provide early warning of releases.”  Often observed is a lack of such detectors in a process, and there is no documentation that the PHA team considered adding additional toxic or combustible gas detectors, likely because it is focused on evaluating the severity/likelihood/risk associated with each deviation, and most of the risks are determined to be acceptable with the safeguards already in place.  It is beneficial to (1) include a requirement to consider whether additional detectors would reduce the overall risk in PHA teams’ scopes/charters and (2) document the results of these evaluations in the PHA reports.

Facility Siting and Human Factors Checklists: Both facility siting and human factors evaluations are typically addressed by completing industry standard checklists in addition to use of standard hazard evaluation methodologies (e.g., hazard and operability [HAZOP]). However, some PHA teams only document the items they had concerns about and do not provide answers to all the  checklist issues.  OSHA views this as documentation “by exception” (see Facility Siting question H.1 in OSHA’s Refinery National Emphasis Program [13]).  Also, it is not uncommon to see unresolved comments requiring some level of follow up that could be recommendations but are not included in the PHA recommendation list.  These issues can be addressed by ensuring PHA teams (1) justify/explain any nonstandard answers in the checklists and (2) resolve comments in the checklists by discussing why they did not believe any action was necessary for items that do not become recommendations.

Completion of PHA Recommendations: PHA recommendations are to be resolved (i.e., reviewed by management, accepted/rejected, and assigned resources for completion with target dates) in a timely matter, and actions taken are to be documented and completed as soon as possible.  However, recommendations are often (1) not promptly resolved (typically within 90 days), (2) rejected without appropriate justification and documentation, and/or (3) not competed in a reasonable time (due to changes in assigned personnel, lack of funding, competing priorities, etc.).  In addition, there is inadequate closure documentation (e.g., records just say “Complete” and do not reference MOC numbers or provide pertinent attachments) or the resolution of a PHA recommendation(s) does not address the specific issue(s) identified. In some cases, the final wording of recommendations is also not updated in the PHA worksheets as the report was edited and finalized. These issues can be addressed through (1) instituting a rigorous process for managing PHA recommendations, including timing requirements; (2) periodic reporting on the status of PHA recommendations, with extra “attention” to those becoming “overdue” or “old;” and (3) cross-checking by supervisors or PSM department personnel of the adequacy of closure documentation.  Care should also be taken to avoid closing recommendations based on the issuance rather than the completion of an MOC or other document that initiates implementation of the action.

Download Full Original Manuscript (PDF). Used with permission.

References

The published version of this complete article can be found on Chemical Processing’s website where you can also access more tools and resources to help you run safe, efficient facilities.

• PSM Audits Unmask Myriad Mistakes
  Co-authored with James R. Thompson, Chemical Processing, pp. 18-25, July 2022
• Operating/Safe Limits Table Issues
• Operating Procedure, Safe Work Practice, and Training Issues
• Mechanical Integrity Issues
• Other PSM Elements