(Adds details)

CARLING (AFP)--A blast at a Total SA (TOT) petrochemicals plant in eastern France killed two people, injured five and left others buried under rubble Wednesday, officials said.

A score of fire engines and 50 firefighters were sent to the plant in Carling after the blast in a steam-cracking furnace which damaged equipment but didn't cause a fire, they said.

The cause of the explosion that happened at 1330 GMT wasn't immediately known, officials said.

The Carling plant produces a range of petrochemicals including ethylene, propylene, methane and styrene, and plastic consumer products such polyethylene and polystyrene, according to Total.

The products are produced by the process of steam cracking, whereby petroleum and either gas oil or naphtha are mixed in a cracking oven with superheated steam at 800 degrees Celsius, the company said.