As officials investigate the recent derailment of a train carrying toxic chemicals in eastern Ohio, concerns about the disaster’s effects on human health and the environment are growing, and experts warned that understanding the causes and consequences could require a more comprehensive investigation than what they have seen so far.
“There’s just a lot of unknowns,” said Donald S. Holmstrom, a former director of the Western Regional Office of the United States Chemical Safety and Hazard Investigation Board, the federal agency that investigates industrial chemical accidents.
The derailment and chemical spill in the town of East Palestine, Ohio, had all the appearances of a nightmare. After the train ran off the tracks on Feb. 3, starting a huge fire, the authorities decided to intentionally burn the chemical cargo in some of the cars rather than risk an explosion or other uncontrolled disaster.
Five of the cars were carrying vinyl chloride, a colorless gas used in making plastic products that can cause dizziness, headaches and drowsiness when inhaled in the short term and a rare form of liver cancer after chronic exposure.
“The volume is just stupendous,” said Gerald Poje, an expert in environmental health and former member of the Chemical Safety Board. “It just is horrific to think about how much was released and how much was purposefully burned.”
The National Transportation Safety Board said its investigation into the causes of the derailment was continuing. The Environmental Protection Agency said it was monitoring the air in buildings and the surrounding area and had not detected any harmful gases in homes so far. Officials said last week that evacuated residents could safely return home.
Mr. Holmstrom managed the Chemical Safety Board’s investigation into the 2010 explosion at the Deepwater Horizon drilling rig in the Gulf of Mexico, which caused the worst offshore spill in American history. He said the Ohio derailment was significant enough that it could merit a presidential commission along the lines of the one that was created after the Deepwater Horizon explosion.
Mr. Holmstrom said such a commission would help to address the many questions about the responsibilities of government agencies and the rail operator, Norfolk Southern, as well as the effects on the community and the environment.
With chemical spills, the threats to human health can linger long after the emergency has been dealt with, said Erik D. Olson, the senior strategic director for health and food at the Natural Resources Defense Council, a nonprofit focused on public health and environment.
“Some of the authorities are telling people that when they return, they should open their windows and wipe down all their surfaces,” Mr. Olson said. “Well, obviously, that means they know that there’s some contamination that remains in the area.”
Particles from a chemical plume can settle on the ground and seep into wells and other drinking water sources. Contaminants in groundwater can vaporize and migrate through cracks into the soil and into basements and homes. “The long-term effects are what often get overlooked,” Mr. Olson said.
“We’re taking this local emergency very seriously and we’ll continue to do everything in our power to protect the community,” Michael S. Regan, the administrator of the Environmental Protection Agency, said on Tuesday. “We stand ready to contribute in any way we can.”
One issue with toxic chemical releases is that the hazards are posed not just by the individual chemicals involved, Dr. Poje said. Chemical compounds can interact with one another in complex ways and persist after burning.
“There could be hundreds of different breakdown products that still remain, for which we have often very poor toxicological profiles,” Dr. Poje said. “We’re oftentimes in this unknown place.”
So far, the derailment’s harm to wildlife has been more immediately apparent than the effects on humans, though extensive questions remain there, too. The spill affected about seven and a half miles of stream, according to the Ohio Department of Natural Resources, and killed an estimated 3,500 fish as of Feb. 8, mostly small suckers, minnows, darters and sculpin. Residents have reported dead or sickened chickens and other animals.
Ecologically, one concern is for hellbenders, a prehistoric-looking aquatic salamander that can reach two feet long and is endangered in Ohio. Fighting drastic population declines, scientists, wildlife officials and other partners have been collecting hellbender eggs in the wild, rearing them in captivity and reintroducing them to the wild at about age three, when they are thought to have a better chance at survival.
One site, where about 250 hellbenders have been released since 2014, is between areas where dead fish have been found since the derailment, said Gregory Lipps, a herpetologist at the Ohio State University who leads the effort.
“So many people have poured so much time and energy into this,” said Mr. Lipps. “Our release site that’s been impacted is in state forest and nature preserve. You look around and think, ‘Boy, this is a nice protected area,’ but you can’t control what comes down the stream, can you?”
Mr. Lipps is hopeful that the torpor-like state that hellbenders are thought to enter during winter will help them survive. “Maybe a short-term exposure to pollutants is not going to be the end of the world,” Mr. Lipps said. “I don’t know.”
Lisa Friedman contributed reporting.
