By Erwin Seba

PORT NECHES, Texas (Reuters) – Three workers were injured in an early morning explosion on Wednesday that sparked a blaze at a Texas petrochemical plant, the latest in a series of chemical plant accidents in the region.

An initial explosion at a TPC Group complex in Port Neches, Texas, was followed by secondary blasts, shattering windows, blowing locked doors off their hinges and prompting officials to evacuate homes within a half-mile radius of the facility, which about 90 miles east of Houston.

Toby Baker, head of the state’s pollution regulator, criticized the “unacceptable trend of significant incidents” in the region and pledged to review the state’s compliance efforts.

The fiery blast follows others at petrochemical producers and storage facilities in Texas. A March blaze at chemical storage complex outside Houston burned for days and was followed a month later by a fire at a KMCO LLC plant northeast of Houston that killed one worker and injured a second. A fire at an Exxon Mobil Corp chemical plant in Baytown, Texas, in July injured 37.

People more than 30 miles away from the complex, which supplies petrochemicals for synthetic rubber and resins and makes a gasoline additive, were shaken awake by the 1 a.m. CT (0700 GMT) explosion, sources familiar with the fire-fighting and rescue operations said.

Some homes close to the plant sustained heavy damage and local police were going door-to-door to check if residents were injured, said the Jefferson County Sheriff’s Office.

One of the three wounded workers was flown by helicopter to a Houston hospital’s burns unit, the sources said.

Peyton Keith, a TPC spokesman, said fire officials were determined to let the fire in a butadiene processing unit burn itself out, and were focused on keeping the flames from spreading. He could not say when the fire could be extinguished.

All three of the workers taken to hospital were treated and released.

There was no immediate information on possible emissions from the blaze, pollution regulator Texas Commission on Environmental Quality said. No impacts to water were reported.

The plant employs 175 people and routinely has 50 contract workers on site. The company said the explosion occurred in a processing unit.

“We cannot speak to the cause of the incident or the extent of damage,” the company said.

TPC processes petrochemicals for use in the manufacture of synthetic rubber, nylon, resins, plastics and MBTE, a gasoline additive. The company supplies more than a third of the feedstock butadiene in North America, according to its website.

“Right now, our focus is on protecting the safety of responders and the public, and minimizing any impact to the environment,” TPC Group added.

(Reporting by Erwin Seba in Houston and K. Sathya Narayanan in Bengaluru; additional reporting by Arpan Varghese, editing by Louise Heavens and Bernadette Baum)