A chemical leak at a DuPont plant outside Houston left four workers dead and one injured Saturday. The leak at the La Porte, Texas, plant occurred about 4 a.m. CST and took about two hours to contain, company officials said.

The chemical, methyl mercaptan, is used to make insecticides and fungicides. It also gives natural gas that rotten-egg smell.

The Houston Chronicle reported a haz-mat crew from the Harris County Fire Marshal's office, along with personnel from La Porte and Deer Park fire departments rushed to the 800-acre complex that employs 320 people. Four other companies also operate out of the site.

The odor from the leak reached as far as 40 miles to Rosenberg and Sugar Land. The company said the leak posed no risk to the public.

Plant manager Randall Clements said the injured employee was hospitalized for observation but expected to make a full recovery, CNN reported. Clements said DuPont would cooperate fully with an investigation into the leak, the Associated Press reported.

"We know something wrong happened today and we are going to do the proper investigation to make sure it doesn't happen again," DuPont spokesman Aaron Woods told the Chronicle.

"Our thoughts and prayers are with the families of the employees."

Methyl mercaptan can cause severe respiratory problems and skin and eye irritation, the Agency for Toxic Substances and Disease Registry notes. It also can lead to headache, dizziness, nausea, vomiting, coma and death.