Officials are trying to determine what caused a chemical gas leak that forced the temporary closure of a heavily used bridge connecting Delaware and New Jersey on one of the busiest travel days of the year.
The leak of highly flammable ethylene oxide from a Croda production facility on Sunday forced the precautionary closure of the Delaware Memorial Bridge for more than six hours as the Thanksgiving holiday weekend wound down.
The bridge carries traffic along Interstate 295, a major East Coast artery, with a daily volume of about 80,000 vehicles.
Cara Eaton, a Croda spokeswoman, said in an email Monday that the company was focused on investigating the matter and that officials were not available for interviews.
A company statement earlier Monday said the Atlas Point facility at the base of the bridge was shut down safely, and that final preparations were being made for an inspection of the plant, so that an investigation can proceed.
"We would like to reassure the public that gas levels were independently monitored during and after the incident and we can confirm that there was no point at which there was an unsafe level detected," the statement read. The company, which is based in the United Kingdom, also said one employee working on the plant at the time decided to seek medical advice as a precaution and was under observation.
"We are very sorry for the significant inconvenience that this had on the community and those travelling nearby," the statement added.
Meanwhile, Delaware environmental secretary Shawn Garvin said state officials, who oversee operations at the facility, do not yet know what happened.
"We are investigating, along with the company, to make some determinations as to what actually did go wrong," Garvin said, adding that the leak apparently was restricted to ethylene oxide.
Ethylene oxide is an ingredient in the production of several industrial chemicals, including ethylene glycol, a compound found in automotive antifreeze and brake fluids, solvents, paints and other industrial and commercial products.
Ethylene oxide, which is also used as an agricultural fumigant and sterilizing agent for medical equipment and supplies, is highly flammable and reactive. Acute exposure can cause respiratory and skin irritation, while chronic exposure has been associated with cancer.
In 2015, Croda was granted a permit under Delaware's Coastal Zone Act, which limits heavy industry in designated coastal areas, to manufacture ethylene oxide from corn-based ethanol. In seeking the permit, the company touted the environmental sustainability benefits of using ethanol instead of petroleum products in the manufacturing process. It also noted that production would eliminate the safety risks involved in transporting ethylene oxide by railcar from the Gulf Coast.
"The process safety aspects of this project have been thoroughly analyzed and addressed," the company said in a slide presentation on its permit request. It also noted that it was following industry standards to guard against accidental chemical releases and would rely on redundant detection systems and use of automated computer control systems to help eliminate human errors.
Croda began production of ethylene oxide on Aug. 24, four days after state officials conducted a partial compliance evaluation of boilers and generators at the facility. In a Sept. 21 letter, a state environmental engineer informed Croda that the August evaluation resulted in an "excellent inspection."
Earlier this month, however, Croda sought a permit modification regarding particulate emissions for a temporary boiler the company was planning to use during maintenance and repair work on two primary boilers.
Croda acquired the Atlas Point site in 2006 from another chemical company, UiQema.