East Deer residents were spared a deadly environmental disaster in their back yards Monday when a derailed tanker leaked its toxic contents into the river instead of the air.
The train car, which holds 15,000 to 20,000 gallons, contained a compressed gas called anhydrous hydrogen fluoride. Released into the air, hydrogen fluoride gas can cause eye, nose and throat irritation and fatal lung damage, according to the federal Agency for Toxic Substances and Disease Registry.
When mixed with water, hydrogen fluoride becomes highly corrosive hydrofluoric acid, which produces fluoride ions. If these ions penetrate the skin, they can cause deep burns, gastric pain, cardiac arrest and death, the agency said.
Though hydrogen fluoride is dangerous in both water and air, East Deer residents and their neighbors were lucky the gas leaked into the Allegheny River — where their chance of exposure is minimal, unless they plan to go swimming — and not into the atmosphere, said Ronald Neufeld, a civil and environmental engineering professor at the University of Pittsburgh.
“The first concern from a human health standpoint is whether anyone was exposed to an aerosol or cloud of hydrogen fluorine gas,” Neufeld said.
Because that didn’t happen, officials must stave off the flow of any hydrogen fluoride leaking from the derailed car and monitor any hydrofluoric acid moving downriver, Neufeld said.
That might not be easy, according to health and safety experts at the scene.
Workers haven’t determined whether the leak is being caused by a hole or an open valve, said Don Bialosky, emergency response coordinator for the state Department of Environmental Protection. The leak likely is coming from the car’s top dome, which covers all valves, but the car sank upside-down, 5 to 10 feet in the water.
“The dome could be smashed right into the mud,” Bialosky said. “There’s no physical way for someone to go in and open it.”
Bob Full, Allegheny County chief of emergency services, said there are no immediate concerns for the safety of nearby residents.
The morning’s cold temperatures caused the gas to evaporate more slowly, forestalling the formation of a deadly cloud, Bialosky said.
Pitt chemistry professor Peter Siska cautioned the onset of more serious health problems because of exposure to hydrogen fluoride can be delayed as fluoride ions penetrate deeper in the body.
“Hydrogen fluoride is one of the worst chemicals to spill,” Siska said. “It can act as a systemic poison with long-lasting effects if you get too much within your body.”
Ideally, rescuers and hazardous materials crews will be able to right the overturned car and patch the leak before removing the tanker from the water. This would prevent any gas from leaking into the air and potentially harming workers or residents.
If workers can’t roll the car into place, officials might choose to leave it in the water until they are sure it’s emptied.
“The water would just dilute the material as it comes out,” Bialosky said.
The derailment poses no immediate threat to drinking water supplies and no water conservation restrictions were imposed, Full said.
Officials with municipal authorities downriver from the spill said they are monitoring their water intake, but hadn’t encountered any dangerous chemical levels.
While drinking water supplies appeared secure, “the acid … could cause death to any wildlife in the area,” Pitt’s Siska said.
“I wouldn’t rule out that there could be some dead fish as a result of this,” Bialosky said.
Water quality experts, chemists and government officials agreed the environmental impact of the derailment could have been much worse.
Earlier this month, a train derailed near a switchyard in Graniteville, S.C., leaking a green cloud of chlorine gas, which is in the same chemical family as hydrogen fluoride. The accident killed nine and forced hundreds of people to evacuate their homes for days.
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