The Associated Press

BRYAN, Texas (AP) - Evacuation orders have been lifted after a fire at a central Texas chemical plant forced thousands of people from their homes and closed Texas A&M University's main campus.

John Salsman with Brazos County emergency management says a welder may have sparked the fire Thursday at El Dorado Chemical Co. plant. It threatened to ignite explosive ammonium nitrate used as a fertilizer ingredient.

Thirty-four people were treated and released from area hospitals.

The plant in Bryan, about 100 miles north of Houston, continued smoldering Friday. The last of the residents who had been evacuated were allowed to return homes, and Texas A&M University reopened its College Station campus.

Officials with the Texas Commission on Environmental Equality are conducting an environmental assessment of the site Friday.