“Proper Handling of Toxic Inhalation Hazard (TIH) Chemicals” featured in the Chemical Engineering Progress (CEP)

The Chemical Engineering Progress journal recently featured the article “Proper Handling of Toxic Inhalation Hazard (TIH) Chemicals,” by Mike Broadribb and Rafael Callejas-Tovar. This article provides guidance for handling TIH chemicals using two types of technical safety studies, which together provide an unbeatable approach to risk management and mitigation:

  1. Risk Based Process Safety (RBPS) approach for auditing TIH risks at chemical plants and along transportation routes.
  2. Quantitative Risk Assessment (QRA) to evaluate the risks associated with handling and transporting TIH chemicals along with a method for selecting appropriate mitigative measures.

Read the abstract to this paper below, and access the full article here. Learn more about transportation risk assessments, and feel free to contact us to speak with Mike and Rafael about guidance on this topic.


This paper was adapted from Mike and Rafael’s 2021 presentation, “I Didn’t Inhale, and Never Tried It Again. Proper Handling of Toxic Inhalation Hazard (TIH) Chemicals in Plants and During Transportation,” developed for the 2021 AIChE Spring Meeting and 17th Global Congress on Process Safety (GCPS).

We’re pleased to continue sharing this guidance, and are eager to present more valuable topics at the 2022 meeting in April! Mike Broadribb will present his topic, “Under Investigation; Wanted, Missing RBPS Elements.”

Learn more about Risk-Based Process Safety here, and stay tuned for more information on BakerRisk’s presentations for the 2022 AIChE Spring Meeting and 18th GCPS!


Numerous fatalities and serious health effects have occurred in the process industries through personnel exposure to toxic chemicals and materials. A Toxic Inhalation Hazard (TIH) chemical can be particularly hazardous as a release of some chemicals cannot be detected through sight or smell. TIH chemicals are widely handled in process units and also transported by road, rail, marine, and pipeline. Fatal incidents involving chlorine (Graniteville, SC, 2005), hydrofluoric acid (South Korea, 2012), and methyl mercaptan (MeSH) (La Porte, TX, 2014) (Ref.1) emphasize the risks of TIH chemicals if they are not handled with a sense of vulnerability and proper care. Most elements of CCPS Risk Based Process Safety (RBPS)(Ref. 2), plus some engineering design considerations, are important for the proper handling of TIH chemicals.

Transportation of TIH chemicals poses additional risks as an accidental release can potentially expose a large public population. In addition to other RBPS elements, hazard identification and risk analysis (HIRA) can be used to quantify the consequences and risks associated with transportation operations. A comprehensive quantitative risk analysis (QRA) involves the development of an event tree to identify scenarios, dispersion simulations to calculate vulnerabilities along the route, and a thorough frequency analysis to pair the scenarios with their likelihood to calculate risk. The results are typically presented in terms of FN curves[1], societal risk, and location specific individual risk, which are compared against risk tolerance thresholds to facilitate the decision-making process. These results have helped companies understand if the benefits of their transportation operations justify the associated risks, and to develop comprehensive risk mitigation strategies.

This paper describes the authors’ experiences of applying: (i) good practices for handling TIH chemicals, (ii) a RBPS approach for assessing TIH risks at chemical plants, including loading/unloading (railcars, road tankers, ISO tanks), (iii) use of quantitative methods for TIH transportation risk decision-making, and (iv) real case examples of potential TIH risk reduction strategies.

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