The Chemical Safety Board says refineries need to strengthen safeguards surrounding the use of hydroflouric acid, and the EPA should take steps to improve oversight. The recommendations are part of a final report on the investigation into the June 2019 explosion and fire at Philadelphia Energy Solutions in southwest Philadelphia.
One of the most dangerous aspects of the incident was the release of more than 5,000 pounds of hydroflouric acid (HF) into the air. Nobody was injured by the chemical release. But it’s one of the most deadly industrial chemicals in use, and swallowing just a small amount of it or getting small splashes on the skin can be fatal, according to the Centers for Disease Control and Prevention.
Integral to the creation of high-octane gasoline, it is used as a catalyst and is combined with highly flammable hydrocarbons at 46 alkylation units in the United States, including three other refineries in the Philadelphia region.
In a gaseous state, the CDC says, low levels of HF can irritate the eyes, nose and respiratory tract. Breathing it at high levels “can cause death from an irregular heartbeat or fluid buildup in the lungs.”
The Chemical Safety Board’s investigation points to a corroded pipe as the source of the explosion. It also says several safety provisions failed to kick in immediately or were not in place.
The piece of pipe, long overdue for replacement, spilled highly combustible hydrocarbons mixed with HF and caused the devastating explosions and fire at the refinery in the early morning of June 21. One explosion sent a 38,000-pound vessel — about the same weight as a firetruck — across the Schuylkill River, where it landed on the waterway’s banks, near the company’s tank farm. In addition to the hydroflouric acid, PES estimates the incident released about 676,000 pounds of hydrocarbons. Most of that — about 608,000 pounds — burned in the fire and explosions.
A critical part of the PES refinery was destroyed, resulting in an estimated $750 million in property damage and leading to a Chapter 11 bankruptcy and the loss of more than 1,000 jobs.
“This is one of the largest refinery disasters worldwide in decades in terms of cost,” said CSB interim executive authority Steve Owens. “The local community in Philadelphia fortunately was not seriously harmed, but given the refinery’s location, it could have been much worse. This incident should be a wake-up call to industry to prevent a similar event from occurring in the future.”
The incident began when a 90-degree piece of pipe known as an “elbow” ruptured, releasing fluid containing hydrocarbons and HF. The report says the pipe was installed in 1973 and contained a higher content of nickel and copper compared to the rest of the piping, causing it to corrode faster.
Petrochemical industry standards are largely self-directed, so any pipes installed before the regulations were updated in 1995 were grandfathered in, despite the fact that the American Petroleum Institute’s own recommended practice for “Safe Operation of Hydrofluoric Acid Alkylation Unit,” last updated in May 2013, states: “HF corrosion has been found to be strongly affected by steel composition and localized corrosion rates can be subtly affected by local chemistry differences.”
The CSB report says the pipe did not meet the safety standards established in 1995. Despite this, evaluation of the pipe required by both OSHA and the EPA never occurred.
“To prevent catastrophic incidents companies and industry trade groups must ensure process safety when new knowledge on hazards is published,” said CSB Supervisory Investigator Lauren Grim.
Pipe maintenance and composition standards are set by industry groups, and refineries generally police themselves.
The report found that the refinery lacked remote emergency isolation valves that would have prevented the flow of HF through the ruptured pipe. Water pumps in place to suppress any accidental release of HF also failed due to the explosion and fire. Spraying water on a release of HF is the best way to minimize the damage. It took a worker 40 minutes to manually turn on a water pump that would lessen the amount of HF released.
The CSB is an independent federal agency that conducts investigations of major accidents and issues reports, but can only make recommendations to industry and regulators. It called on the American Petroleum Institute to update their safety standards.
An API spokesperson said the standards are “reviewed and updated on a regular basis.”
“We are reviewing the CSB’s recommendation and look forward to continuing to work collaboratively with the Board to ensure the safety of our nation’s refining infrastructure,” said API spokesperson Scott Lauermann.
Hydrofluoric acid is regulated by both the Environmental Protection Agency and the Occupational Safety and Health Administration.
OSHA does so under the Process Safety Management of Highly Hazardous Chemicals.
The EPA’s Risk Management Plan Rule governs public disclosures surrounding the use and accidental release of toxic chemicals, as well as emergency response.
Several safer alternatives to using hydroflouric acid as a catalyst have been developed, including the use of sulfuric acid. But there is no federal regulatory requirement for refiners to use or even consider these alternatives. The CSB recommends the EPA require refineries to conduct analysis of alternatives as part of the RMP rule.
It also urged the EPA to further study HF under the Toxic Substances Control Act. If the EPA determines it is a “high priority substance for risk evaluation” then it should “conduct TSCA risk evaluation of HF” and put in place policies to mitigate that risk, according to the report.
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