'We need to know the details': Croda neighbors have ‘right to know’ extent of gas leak

CORRECTION: Shortly before the bridge could reopen, George Greenley said 30 percent of the contents of a storage tank still needed to be transferred to another tank.

Croda Inc. said: Ethylene oxide found leaking at its Atlas Point facility near the Delaware Memorial Bridge on Sunday night never reached unsafe levels beyond its property.

State environmental officials said: They won't know how much of the gas leaked until they conduct an investigation.

Holloway Terrace Fire Company spokesman George Greenley said: Product had to be transferred from one storage tank to another before the problem could be mitigated.

Late Tuesday afternoon, the company said the leak was caused by an incorrect gasket fitted on one of the pipes at the company's new bio-ethanol manufacturing operation at Atlas Point.

They said they will not manufacture more ethylene oxide onsite until they are "confident that the plant can resume safe operations."

But it remains unclear how much gas escaped or how long it will take the state and company to release that information.

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That also means no one can say whether the people and motorists nearby faced imminent danger from a chemical that is not only carcinogenic and flammable but also highly explosive.

“It all depends on the amount of ethylene oxide,” said Dr. Bala Subramaniam, a distinguished professor of chemical and petroleum engineering at the University of Kansas. “What is known is that there was a leak and nothing else. We need to know the details.”

Despite assurances from Croda that the risk was low as firetrucks and first responders surrounded the plant on Sunday night, Croda officials asked to shut down traffic on the Delaware Memorial Bridge from about 5 to 11 p.m. 

However, Shawn Garvin, secretary of the Delaware Department of Natural Resources and Environmental Control, said on Monday that nearby state "air monitoring readings confirmed they were over the appropriate levels" as the gas was carried by wind heading toward I-295 and the bridge.

Worries about people inhaling the gas or it catching on fire prompted the shutdown of traffic, he said.

The following day, some people reported they had smelled the sweet, etherlike odor indicative of higher concentrations of ethylene oxide. Others said they had headaches from the fumes while they sat trapped in traffic.

They do not know if they inhaled the poisonous gas, but decades of studies on ethylene oxide show that it takes a relatively high concentration of the chemical to cause those health problems.

GAS LEAK:Fears of car fires, chemical exposure near Delaware Memorial Bridge

It is possible that those smelling the gas were in a place where the wind had carried a pocket of concentrated ethylene oxide. Generally, that sweet odor is not detected below 500 parts per million – a concentration high enough to be toxic to humans over short periods of time, according to the U.S. Centers for Disease Control and Prevention.

“I think everybody has a right to know that the leak is indeed contained, why it happened and what steps will be taken so that it won’t happen in the future,” Subramaniam said. “People should really press for that. That’s certainly their right to know.”

The why, answered late Tuesday, prompted a "systematic review of all other equipment on the ethylene oxide plant pipework," the company said. Officials estimate that review will take about two weeks.

What is known is that ethylene oxide – a human carcinogen used in a slew of products and manufacturing processes that reportedly leaked from a storage tank at Croda’s plant north of New Castle – is highly flammable and explosive, and can cause both minor and serious health problems.

“Anywhere between 200-700 parts per million, you’ll begin to actually smell ethylene oxide … and that’s definitely a level where even a few minutes [of exposure] can cause irritation of the eyes, respiratory tract and so forth,” said Subramaniam, who also is executive editor of the American Chemical Society’s Sustainable Chemistry and Engineering journal.

Fire and explosions often go hand in hand

While Garvin said the biggest concern beyond health impacts was fire, experts and research on the chemical say the explosive nature of ethylene oxide can pose a massive threat from any flame.

“With a spark, it ignites,” Subramaniam said. “And then it decomposes explosively because of the snowball effect created by the heat.”

But unless state or company officials release vital information about how much ethylene oxide leaked because of that incorrect gasket, no one will know if their homes, cars or lives were at risk of massive explosions.

“The higher the leakage, the higher the risk of explosive vapors – and that’s really the main concern with ethylene oxide," Subramaniam said.

The most recent incident with the gas causing injuries reported to OSHA occurred in 2004 at a Sterigenics plant in California where the chemical is used to sterilize medical equipment. An equipment malfunction involving 62 pounds of ethylene oxide caused an explosion that resulted in extensive damage and injured four employees.

That is a mild incident compared with those decades ago that illustrate exactly how reactive, volatile and explosive this widely used chemical can be. According to the American Chemistry Council, explosions from ethylene oxide can have devastating — and far-reaching — impacts.

In a 1962 incident, an ethylene oxide storage unit was contaminated by ammonia, causing a reaction that overpressured and ruptured the vessel and caused an explosion at a plant in Kentucky.

That explosion damaged everything within a 500-foot radius and could be heard more than 20 miles away. That first tank explosion set off a chain reaction of fires and blasted a nearby storage tank into a structure 400 feet away, according to the council's 2007 report on ethylene oxide.

That report outlines more than a dozen other catastrophic incidents involving fires and explosions stemming from ethylene oxide leaks and contamination. Some led to severe injuries and death.

Ethylene oxide has been produced around the world for more than a century, and the tragic lessons learned in that time have led to safer handling practices.

“The current ethylene oxide technology is quite mature,” Subramaniam said. “It’s rare to see accidents with that technology because it has, over the years, developed into a safe technology.”

Just as an airplane faced inherit risk each time it defies gravity, the same goes for handling ethylene oxide.

“I’d say this is quite unusual for an ethylene oxide technology, simply because it’s not new,” he said. “There are a lot of ethylene oxide plants that are running safety day in and day out.”

Ethylene oxide ranks 26th in volume among major industrial chemicals produced in the U.S., according to the CDC. Internationally, it is used as a fumigant and fungicide, to make ethylene glycol for antifreeze, to sterilize medical equipment and other consumer goods, and as a chemical intermediate.

At Croda, ethylene oxide is used in the company’s products, which include non-ionic surfactants that are sold to industrial users. They use it to make liquids that combine mixtures that otherwise would separate, like face creams and cosmetics.

About three months ago, Croda began manufacturing ethylene oxide with corn-based ethanol at its Atlas Point facility near the Delaware Memorial Bridge.

Possible that leak’s risk was low

In an open-air environment, it is possible that even a large amount of ethylene oxide could be quickly dispersed. While ethylene oxide is heavier than air and tends to form vapor clouds when it escapes, windy conditions can make all the difference.

Just like airing out a home from a carbon monoxide leak, dispersing the gas often is the best solution. On Sunday, emergency crews sprayed water in the air to try to dissipate the gas.

Unlike an oil spill on water, which is relatively slow-moving and can be contained, whatever gas leaked from the Croda tank is lost to the atmosphere.

“It can travel as far as the wind can take it,” Subramaniam said. 

Without knowing how much of the gas had leaked, but knowing the risks of a spark finding its way into an ethylene oxide vapor cloud, Subramaniam said the call to shut down the bridge was right.

“It’s certainly a precautionary measure and a prudent one because, depending on the amount of the ethylene oxide leak, the risk is proportional to that,” he said.

While the Croda plant predates the Delaware Memorial Bridge, Garvin said, its bio-ethanol-based manufacturing of ethylene oxide does not. The state granted a permit to build that new plant in 2015. Operations officially began when the first ethylene oxide was stored in tanks onsite in late August 2018, documents show.

"The goal is to make sure everything is operating properly," Garvin said. Approval of the new operation was appropriate because "it met all the criteria," he said.

Contact reporter Maddy Lauria at (302) 345-0608, mlauria@delawareonline.com or on Twitter @MaddyinMilford.

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