Two chemicals, butyl acrylate and vinyl chloride, have previously been disclosed, with vinyl chloride leading to a mandatory evacuation last Monday.
In its letter to the company, EPA listed the three other chemicals involved in the derailment: ethylhexyl acrylate, which can cause burning on the skin and in the eyes, coughing and shortness of breath; isobutylene, which can make people dizzy and drowsy; and ethylene glycol monobutyl ether which can cause coughing, dizziness, drowsiness, headaches, nausea, and weakness if inhaled.