Scientists will be likely monitoring the ecosystem surrounding the areas affected by a massive chemical spill in Ohio for years to come.

The tens of thousands of aquatic life that have died as a result could potentially point to whether ecosystems are safe enough for human activity to persist nearby, experts tell ABC News.

A train carrying several toxic chemicals derailed in East Palestine on Feb. 3, spilling cars full of hazardous materials onto the soil surrounding the derailment.

A controlled burn that occurred over the next several days then expelled even more toxic gases, prompting a mandatory evacuation for residents living within a 1-mile radius of the crash site due to the potentially deadly risks posed by inhalation in high concentrations.

Health officials immediately began testing the soil, air and land to ensure humans were safe to return. While the evacuation order was lifted on Feb. 8, the Ohio Department of Natural Resources announced on Feb. 14 that at least 3,500 aquatic animals along the Ohio River had died as a result of pollutants from the controlled burn seeping into the streams.

By Feb. 23, the number of animals that had died in and around East Palestine jumped to more than 43,000. This is significant because Ohio uses the fish community as an overall indicator of water quality, Michael Booth, a research professor of fish and aquatic ecology at the University of Cincinnati, told ABC News.

“Usually, you can use the community of fish as an indication of what the water quality is at any given time,” Booth said.

In addition, 11 animals have been submitted for testing to determine whether their deaths were related to the chemical spill, according to the Ohio Department of Natural Resources.

Experts explore how the ecosystem will recover

Ohio officials tend to use fish as an indicator of water quality because they live in it, so they are exposed to any impurities at a much higher rate, Booth said.

“If you have a mass die-off, that’s a pretty good indication you shouldn’t be making contact with that water,” he said.

Although none of the aquatic animals …