(54ct) The Definition of Feasibility as it Applies to Inherent Safety

One of the most difficult technical concepts facing industry and regulators in the implementation of inherent safety is that inherent safety may be theoretically possible in many cases, but may not be feasible. This term has wide interpretation and application since inherent safety became a formal requirement in process safety (and security) programs approximately ten years ago. Inherent safety regulations in three jurisdictions, Contra Costa County, CA, the State of new Jersey, and most recently in the State of California for oil refineries, this term has been used as a qualitative measure to help determine whether a particular inherent safety measure should or should not be implemented. Underlying its use is the principle that a claim of infeasibility of an inherently safer measure shall not be based solely on evidence of reduced profits or increased costs.

Contra Costa Health Services defines “feasible” as “capable of being accomplished in a successful manner within a reasonable period of time, taking into account economic, environmental, legal, social, and technological factors.” However, a claim of financial infeasibility “shall not be based solely on evidence of reduced profits or increased costs, but rather shall include evidence that the financial impacts would be sufficiently severe to render the inherently safer system as impractical.” This contention shall be supported by sufficient evidence to demonstrate that implementing this inherently safer system is impractical, and the reasons for this conclusion.

The New Jersey Department of Environmental Protection guidance for the Toxic Catastrophe Prevention Act (TCPA) regulations contains more detailed criteria for determining the feasibility or infeasibility of an inherent safety measure. This detailed guidance includes criteria for:

Environmental and Public Health and Safety Feasibility, Legal Feasibility, Technological Feasibility, and Economic Feasibility. Quantitative and/or qualitative justification is required to use these criteria. Generally, an IS measure is considered feasible if it has been successfully applied to similar processes or similar situations unless there are unique circumstances at a given facility that would prevent its application.

Consensus evaluation methods that examine all of the relevant factors in feasibility are currently not available. New Jersey’s inherent safety guidance provides the most detailed criteria published thus far, but these criteria, or variants of them have yet to be adopted in other jurisdictions or voluntarily by industry. However, it is clear that feasibility is a multi-faceted examination that is specific to each inherently safety measure proposed and specific to each facility and its risk profile, and is also specific to other industrial sectors that might be affected by potential risk transfer. Feasibility also includes economic feasibility. Methods to estimate the value of inherent safety measures and to quantitatively assess whether a given process is “as inherently safe as is practicable” are currently unavailable or unproven.

Both the public and regulators may have higher risk reduction expectations of inherent approaches than what is ultimately found to be feasible in a given application. The public and regulators expect to see a realistic effort to apply first- and second-order inherent safety to achieve major risk reduction. However, only considering first- or second-order IS may be at odds with other practical and cost-effective risk reduction options, especially for existing processes. A facility may conclude that IS is infeasible if it does not look at all IS options. This difference between public and industry perceptions of risk—and a misunderstanding or lack of appreciation of the impacts of some ISS modifications - may create a barrier to common expectations, and to an accepted definition of “feasibility.” Any move in an inherently safer direction is likely to be a good risk reduction move, and should be encouraged.