MOSES LAKE, Wash. -

Moses Lake residents were asked to stay inside their homes with all doors and windows shut for two hours Friday, following a chemical leak at REC Silicon Inc.

Kyle Foreman from the Grant County Sheriff's Office said it was a "serious situation."

According to Steve Reed from National Foods in Moses Lake, at 7:05 a.m., he heard sirens coming from the plant and saw a cloud of smoke above the plant.

Ten minutes later, he received a reverse 911 call warning people to stay inside, with their doors and windows shut.

The cloud traveled eight miles to Warden and four miles to Interstate 90 before dissipating.

I-90 was closed in both directions for about an hour after the leak for precautions.

The plant sent an air sampling team into the area and they are tracking the vapor cloud. As of now, they do not know what the chemical was.

According to an REC employee, at 3 a.m. Friday, REC Silicon Inc. noticed a problem with machinery in the building where the explosion occurred. They were in the process of temporarily shutting down the building until they could find out what was wrong.

The employee does not know if they successfully shut down the machinery before the explosion.

According to him, the product is a caustic gas.