An explosion at a Texas fertilizer plant in a small town near Waco has injured 200 people and destroyed dozens of homes and businesses, an emergency official said.

Of the 200 people injured, 40 were injured critically, Texas Department of Public Safety spokesman Gail Scarborough said. It was unclear whether or not there were deaths.

Besides the injuries, 75 to 100 houses and business were completely destroyed in and around the plant.

Firefighters were on scene of a structure fire at the West, Texas, fertilizer plant.

"They are still on scene, assessing the scene, treating the injuries, taking injured to the hospitals," Dani Moore, a spokeswoman for State Highway Patrol told ABC News Radio.

It was unclear what caused the explosion.

At least 10 buildings in the town of West were on fire, including a school located next to the plant, ABC News affiliate WFAA reported.

The town of West has a population of about 2,800.