Inherently Safer Technology - A Chemical Switching Case Study

Inherently Safer Technology (IST) is a concept that has garnered attention recently in part due to the issuance of Executive Order 13650 – Improving Chemical Facility Safety and Security in August 2013. Additionally, promoting safer technologies and alternatives was a component of subsequent information requests from both EPA and OSHA specific to potential amendments to the Chemical Accident Prevention (a.k.a. RMP) and Process Safety Management (PSM) programs, respectively. IST was formally made a part of RMP through amendments promulgated on January 13, 2017, with a current effective date of February 19, 2019. IST stems from the industrial hygiene principal known as hierarchy of controls where a hazard is ideally eliminated at its source before applying less effective controls. A common example is the replacement of a hazardous chemical for a less dangerous formulation or alternative such as replacing anhydrous ammonia with a lower concentration of aqueous ammonia when it is applied for the control of nitrogen oxide (NOx) at electric generating facilities. For this study, an evaluation was made of the hazards, effectiveness, and costs associated with transporting, storing, and using different forms of ammonia for NOx control. Additionally, the cost of switching from one chemical to a less hazardous concentration was determined for a standard configuration. Finally, a general recommendation was developed to inform existing plants of their retrofit options and to support design and permitting for future development.