At least one person was killed and 30 others were injured in a huge explosion followed by a fire at a chemical plant in Geismar, Louisiana, the state police reported.

At the time of the blast, there were about 600 workers at the plant, state police Capt. Doug Cain said.

At least 30 people were injured and taken by ambulance and helicopter to hospitals in the area.

The explosion occurred shortly after 8:30 a.m. and two hours later police blocked off the surrounding roadways.

At 1 p.m., state police said that the fire had been extinguished and that the situation was under control.

The state Department of Environmental Quality sent teams to the site to evaluate the air quality, spokeswoman Jean Kelly said.

The chemical plant belongs to The Williams Companies Inc., based in Tulsa, Oklahoma.

The firm's Geismar plant produces some 1.3 billion pounds of ethylene and 90 million pounds of polymer grade propylene every year.

Ethylene is a colorless and flammable gas that is widely used in the chemical industry. EFE