What-If/Checklist Analysis (WICL) Protocol

What-If/Checklist is a hazard identification technique used when the investigative team may be new or unfamiliar with other more rigorous hazard identification techniques. It is especially valuable when team participants may not be trained engineers in the area but have considerable experience with the process or operation studied. The organization follows the Process Hazard Analysis Protocol published as a common approach for all methodical hazard identification studies.


In WICL initially the team does focused brainstorming hazard identification and the facilitator/leader then stimulates the team further in each area or unit operation considered with additional questions that have been developed as a result of other similar studies. AICHE-CCPS has published a checklist in their “Guidelines for Hazard Evaluation Procedures” second edition, 1992, that serves this need well for chemical process hazards consistent with OSHA 1910.119 needs. The technique works well with other industries also. The process or operation is examined in all modes of operation: Run, Idle, Startup, Shutdown, and Emergency Shutdown.


Using a Checklist in this protocol reduces the number of gaps or oversights in a safety study. The checklist is meant to derive more thought about the possible hazards. Many times the What-If brainstorming does not consider what-if questions beyond simple one-step deductions. However, most hazards occur because of pre-existing conditions, which requires the subject matter expert team to do multi-step deductions to reason how a hazard may be created. The checklist also works well to restart a team that has become fatigued by the hazard identification brainstorming process.


Reasons for overlooking items in a structured brainstorm technique can vary. The most frequent problem is a lack of sufficient descriptive information about the process or operation being studied. The checklist is not to be relied upon as the sole source of the study, but should augment what the team has uncovered or begun to uncover in the What-If phase of the examination.

As with any hazard study, a WICL should use a line by line structured question and answer technique. In all cases energy of one form or another is being used which must be controlled in a safe manner or some unwanted consequence must may result. In chemical operations this can be temperature and pressure, potential or kinetic energy. In other operations perhaps fewer or different manifestations of energy are present and the system involved must adequately control the full range of energy. At times a challenge arises when the team does not realize the full scope of how the energy is controlled, and this leads to further study or the need for outside expert input to define to the team the extent of the effects of loss of energy control.

Reporting and follow-up of hazards discovered follow the PHA report guidance.

Contact MATRIC to initiate a discussion on the various ways we can assist in leading, facilitating, or participating in a What-If/Checklist analysis.

Contact MATRIC to initiate a discussion on the various ways we can assist in leading, facilitating, or participating in a What-If/Checklist analysis.

WICL involves a stepwise questioning by a team of experts about every facet of the process. The work process is structured, but the questions originate from the cumulative expertise of the team.


Safety Engineering