A massive pipeline fire in the Houston area sparked grass fires on Monday morning, with at least 100 firefighters battling huge flames.

While the fire was contained several hours later, multiple homes, schools and businesses were evacuated,according to Jamie Galloway, who is the director of community services for the La Porte Office of Emergency Management.

Authorities said at least one firefighter was hurt at the scene, authorities said, adding that the injuries were minor.

In a statement posted online, officials said schools are sheltering in place as fire crews work to put out smaller grass fires.

“Please avoid the area and follow law enforcement direction,” the statement noted. “Further details will be released as available.”

Flames broke out along a block of Spencer Highway, which is near the La Porte/Deer Park line, shortly before 10 a.m.

La Porte City Secretary Lee Woodward told KTRK-TV they don’t yet know what flows through the pipeline or how it will be shut down.

Video images from KTRK showed a park near the fire had been damaged and firefighters pouring water on adjacent homes.

There are also several businesses nearby, including a Walmart.The area where the explosion happened is the site of multiple pipelines including routes for petroleum, ethane, and methanol. It wasn’t clear what exactly had ignited, with the cause of the fire is under investigation.