Regulators are still working to extinguish a fire at the site of the train derailment and chemical spill in southwest Jefferson County. But work has also begun to determine the environmental and health effects of the toxic chemicals that have already leaked.

Both butadiene and styrene monomer have spilled near the site, and environmental regulators are there to determine the extent of the damage. It’s believed the fire is caused by residual butadiene left in its tank, and a lot of the environmental work is on hold until the fire is extinguished.

Vast quantities of water are necessary to fight the fire, but that water has caused additional complications for those trying to contain the toxic chemicals from spreading. Kevin Strohmeier is an environmental inspector with the Kentucky Department for Environmental Protection. He says contractors dug retention areas near the site to catch the water, but:

“That was for just a release from the tanks, as a way of catching things,” he said. “We hadn’t anticipated all of this fire suppression water going on there.”

Air sampling a half mile away from the derailment doesn’t show any signs of toxic chemicals. Strohmeier says his team has also taken water samples from the nearby Ohio and Salt Rivers, and found no evidence of butadiene or styrene from the leaks.

But there’s still lots of work to be done before the threat of further toxic contamination and health effects are gone. Of particular worry are two tanks of hydrogen fluoride. That chemical is a corrosive gas which turns into hydrofluoric acid when it comes into contact with human tissue, and can cause severe burns and even death.

Erica Peterson is WFPL's News Director.