US CSB calls for review to improve HF safety

Assurances needed that “plans are adequate to prevent catastrophic release”

THE US Chemical Safety and Hazard Investigation Board (CSB), has released a letter calling on the US Environmental Protection Agency (EPA) to review and update its 1993 study of hydrofluoric acid (HF) to improve safety.

HF is a highly toxic chemical which can cause injury or death at a concentration of 30 ppm. It is used in about one-third of the US’ refineries. In refineries, HF is used as a catalyst to produce high octane gasoline through alkylation. Alkylation is used to convert isobutane and low-molecular-weight alkenes into alkylate, a high-octane component. The process is carried out in the presence of a strong acid, such as HF.

In the past four years the CSB has investigated two petroleum refinery incidents in which explosions increased the threat of possible HF or modified HF release, says the letter. The first was in 2015 when an explosion occurred at a former ExxonMobil refinery in California, US. The second occurred in 2018 when an explosion occurred at a Husky refinery in Wisconsin, US.

In the course of both investigations the CSB found that members of the communities surrounding the refineries were concerned about the use of HF in the facilities. The public’s concerns related to the adequacy of risk management strategies to protect against release of HF, and the effectiveness of community notification procedures in the event of a catastrophic release.

As a result, the CSB strongly encourages the EPA to review and update its existing study of HF in order to determine whether current refinery risk management plans are sufficient to prevent catastrophic releases. Additionally, the EPA should determine whether there are safer and commercially-available alkylation technologies which could be used in petroleum refinery, says the letter.

Kristen Kulinowski, Interim Executive at CSB, said: “The EPA is the appropriate agency to assess the adequacy of risk management for the use of chemicals like HF. Refiners, their workforce and communities that surround the refineries need assurances that the risk plans are adequate to prevent a catastrophic release.” 

Alternatives to hydrofluoric acid