The key provision of PSM is process hazard analysis (PHA)—a
careful review of what could go wrong and what safeguards must be
implemented to prevent releases of hazardous chemicals. Covered
employers must identify those processes that pose the greatest risks
and begin evaluating those first. PHAs must be completed as soon as
possible. At least one-quarter of the processes must be evaluated by
May 26, 1994, with an additional 25 percent completed each following
year so that by May 26, 1997, if not sooner, employers will have
evaluated all affected processes. PSM clarifies the responsibilities of
employers and contractors involved in work that affects or takes
place near covered processes to ensure that the safety of both plant
and contractor employees is considered. The standard also mandates
written operating procedures; employee training; prestartup safety
reviews; evaluation of mechanical integrity of critical equipment; and
written procedures for managing change. PSM specifies a permit
system for hot work; investigation of incidents involving releases ornear misses of covered chemicals; emergency, action plans; compliance
audits at least every three years; and trade secret protection.
To understand PSM and its requirements, employers and employees
need to understand how OSHA uses the term “process” in PSM.
Process means any activity involving a highly hazardous chemical
including using, storing, manufacturing, handling, or moving such
chemicals at the site, or any combination of these activities. For
purposes of this definition, any group of vessels that are interconnected,
and separate vessels located in a way that could involve a
highly hazardous chemical in a potential release, are considered a
single process.