Chambers County Judge Jimmy Sylvia said firefighters contained the blaze at the Enterprise Products plant in Mont Belvieu about 30 miles east of Houston.
A series of explosions rocked the facility shortly after noon, local time.
The plant processes and stores natural gas liquids and employs between 600 and 700 workers.
There have been no reports of injuries or deaths so far and no evacuations.
However, one contractor is reportedly missing.
Some witnesses said he was seen running away from the blaze.
A nearby elementary school ordered students to stay indoors as a precaution.
Witnesses up to seven miles away reported seeing flames shoot into the sky.
The plumes of smoke were picked up on Doppler weather radar.
The heat from the blasts was so intense it ignited trucks in the plant's parking lot.
The cause is still under investigation.
(Copyright 2011 by VERTEXNews/Newsroom Solutions)