The fiery blast inside a distillation column at the Port Neches, Texas, TPC Group facility on Wednesday injured three workers, blew locked doors off their hinges and spewed a plume of toxic chemicals for kilometres.

The plant manufactures petrochemicals used to make rubber and resins, and the volatile organic compounds in the explosion’s smoke can lead to eye, nose and throat irritation, shortness of breath, headaches and nausea, the pollution regulator Texas Commission on Environmental Quality (TCEQ) said.

No impact to water was reported.

The plant, 145km east of Houston, has a long history of environmental violations and has been out of compliance with federal clean air laws for years, according to the Texas Tribune and state records; it was also declared a high priority violator by the Environmental Protection Agency.

State agencies are monitoring air quality. Police are patrolling the evacuated communities to prevent looting.

TPC spokesperson Sara Cronin said that it was uncertain when the fire would be extinguished or the chemicals burned off but pointed the public to the company’s emergency response website at www.portnechesresponse.com.

The explosion was the fourth major petrochemical fire in the region this year.

Early on Wednesday morning, people more than 48km away from the complex were shaken awake by the 1am blast, sources familiar with the firefighting and rescue operations said.

The blast collapsed a roof over the plant’s control room, sending workers fleeing, and damaged its firefighting system.

Some homes close to the plant also sustained heavy damage, and police went door-to-door early in the morning to check if residents were injured, said the Jefferson County Sheriff’s Office.