Ohio Department of Natural Resources officials say tens of thousands of animals have died in the three weeks since the chemical train wreck in and around East Palestine, USA Today reports.

Experts estimate the number of dead animals to be at least 43,000 fish and other animals. These include gudgeons, crayfish, frogs, and amphibians. However, the department reported that none of the killed species are endangered.

The U.S. Environmental Protection Agency has identified four other substances that entered the air, water and soil during the crash: butyl acrylate, ethylhexyl acrylate, ethylene glycol monobutyl ether and isobutylene. Experts are now continuing to monitor the environmental impact of the accident. An exact estimate of the time it will take to restore the environmental system is not yet available.