As officers examine the current derailment of a prepare carrying poisonous chemical compounds in japanese Ohio, issues concerning the catastrophe’s results on human well being and the atmosphere are rising, and consultants warned that understanding the causes and penalties might require a extra complete investigation than what they’ve seen up to now.

“There’s simply plenty of unknowns,” stated Donald S. Holmstrom, a former director of the Western Regional Workplace of america Chemical Security and Hazard Investigation Board, the federal company that investigates industrial chemical accidents.

The derailment and chemical spill within the city of East Palestine, Ohio, had all of the appearances of a nightmare. After the prepare ran off the tracks on Feb. 3, beginning an enormous fireplace, the authorities determined to deliberately burn the chemical cargo in among the vehicles somewhat than danger an explosion or different uncontrolled catastrophe.

5 of the vehicles have been carrying vinyl chloride, a colorless gasoline utilized in making plastic merchandise that may trigger dizziness, complications and drowsiness when inhaled within the brief time period and a uncommon type of liver most cancers after power publicity.

“The quantity is simply stupendous,” stated Gerald Poje, an skilled in environmental well being and former member of the Chemical Security Board. “It simply is horrific to consider how a lot was launched and the way a lot was purposefully burned.”

The Nationwide Transportation Security Board stated its investigation into the causes of the derailment was persevering with. The Environmental Safety Company stated it was monitoring the air in buildings and the encircling space and had not detected any dangerous gases in houses up to now. Officers stated final week that evacuated residents might safely return dwelling.

Mr. Holmstrom managed the Chemical Security Board’s investigation into the 2010 explosion on the Deepwater Horizon drilling rig within the Gulf of Mexico, which triggered the worst offshore spill in American historical past. He stated the Ohio derailment was important sufficient that it might benefit a presidential fee alongside the traces of the one which was created after the Deepwater Horizon explosion.

Mr. Holmstrom stated such a fee would assist to handle the many questions on the obligations of presidency companies and the rail operator, Norfolk Southern, in addition to the consequences on the neighborhood and the atmosphere.

With chemical spills, the threats to human well being can linger lengthy after the emergency has been handled, stated Erik D. Olson, the senior strategic director for well being and meals on the Pure Assets Protection Council, a nonprofit targeted on public well being and atmosphere.

“A few of the authorities are telling those that once they return, they need to open their home windows and wipe down all their surfaces,” Mr. Olson stated. “Properly, clearly, which means they know that there’s some contamination that continues to be within the space.”

Particles from a chemical plume can decide on the bottom and seep into wells and different consuming water sources. Contaminants in groundwater can vaporize and migrate via cracks into the soil and into basements and houses. “The long-term results are what typically get neglected,” Mr. Olson stated.

“We’re taking this native emergency very severely and we’ll proceed to do every part in our energy to guard the neighborhood,” Michael S. Regan, the administrator of the Environmental Safety Company, stated on Tuesday. “We stand able to contribute in any method we are able to.”

One challenge with poisonous chemical releases is that the hazards are posed not simply by the person chemical compounds concerned, Dr. Poje stated. Chemical compounds can work together with each other in advanced methods and persist after burning.

“There may very well be lots of of various breakdown merchandise that also stay, for which we have now typically very poor toxicological profiles,” Dr. Poje stated. “We’re oftentimes on this unknown place.”

Up to now, the derailment’s hurt to wildlife has been extra instantly obvious than the consequences on people, although intensive questions stay there, too. The spill affected about seven and a half miles of stream, in keeping with the Ohio Division of Pure Assets, and killed an estimated 3,500 fish as of Feb. 8, largely small suckers, minnows, darters and sculpin. Residents have reported lifeless or sickened chickens and different animals.

Ecologically, one concern is for hellbenders, a prehistoric-looking aquatic salamander that may attain two toes lengthy and is endangered in Ohio. Preventing drastic inhabitants declines, scientists, wildlife officers and different companions have been amassing hellbender eggs within the wild, rearing them in captivity and reintroducing them to the wild at about age three, when they’re thought to have a greater probability at survival.

One web site, the place about 250 hellbenders have been launched since 2014, is between areas the place lifeless fish have been discovered because the derailment, stated Gregory Lipps, a herpetologist on the Ohio State College who leads the trouble.

“So many individuals have poured a lot time and power into this,” stated Mr. Lipps. “Our launch web site that’s been impacted is in state forest and nature protect. You go searching and assume, ‘Boy, this can be a good protected space,’ however you may’t management what comes down the stream, are you able to?”

Mr. Lipps is hopeful that the torpor-like state that hellbenders are thought to enter throughout winter will assist them survive. “Possibly a short-term publicity to pollution shouldn’t be going to be the top of the world,” Mr. Lipps stated. “I don’t know.”

Lisa Friedman contributed reporting.