DEER PARK, Texas (AP) — Toxic wastewater used to extinguish the fire following the train derailment in East Palestine is headed to a Houston suburb for disposal, according to the Associated Press. Most of the contaminated soil is going to Michigan.

The wastewater is being sent to Texas Molecular, which injects hazardous waste into the ground for disposal.

A Texas county official says there are outstanding questions about the transportation and disposal of the toxic wastewater that has been moved to a Houston suburb from East Palestine.

Harris County Judge Lina Hidalgo says 500,000 gallons of wastewater from the fiery Feb. 3 derailment has been delivered to Deer Park, Texas, with 1.5 million more gallons set to arrive.

The wastewater has been delivered to Texas Molecular, which injects hazardous waste into the ground for disposal. The company tells television station KHOU it is experienced in disposing hazardous material.

The company told KHOU-TV it is experienced in managing this type of disposal.

“Our technology safely removes hazardous constituents from the biosphere. We are part of the solution to reduce risk and protect the environment, whether in our local area or other places that need the capabilities we offer to protect the environment,” the company said.

The derailment prompted evacuations when toxic chemicals were burned after being released from five derailed tanker rail cars carrying vinyl chloride that were in danger of exploding.

“It’s … very, very toxic,” said Dr. George Guillen, the executive director of the Environmental Institute of Houston, but the risk to the public is minimal.

“This injection, in some cases, is usually 4,000 or 5,000 feet down below any kind of drinking water aquifer,” Guillen added, who is also a professor of biology and environmental science at the University of Houston-Clear Lake.

Both Guillen and Deer Park resident Tammy Baxter said their greatest concerns are transporting the chemicals more than 1,300 miles from East Palestine to Deer Park, Texas.

“There has to be a closer deep well injection,” Baxter told KTRK. “It’s foolish to put it on the roadway. We have accidents on a regular basis … It is silly to move it that far.”

In addition, Ohio EPA said that the process to remove the contaminated soil from the site of the derailment began Thursday.

Under the direction of the Ohio EPA, Norfolk Southern brought in large dump trucks to move contaminated soil to U.S. Ecology Wayne Disposal, a licensed hazardous waste disposal facility in Michigan. This will be a continuous effort to properly manage and safely dispose of the waste.

So far, 4,832 cubic yards of soil have been excavated from the ground and more may be removed as cleanup proceeds. When the process begins to dig up the tracks and remove the soil underneath, that soil will be hauled away immediately and taken to a proper disposal facility.

A total of 1,715,433 gallons of contaminated liquid have also been removed from the immediate site of the derailment. Of this, 1,133,933 gallons have been hauled off-site, with most going to Texas Molecular. A smaller amount of waste has been directed to Vickery Environmental in Vickery, Ohio.

Transportation Secretary Pete Buttigieg, who visited the derailment site Thursday, has warned the railroad responsible for the derailment, Norfolk Southern, to fulfill its promises to clean up the mess just outside East Palestine and help the town recover.

Buttigieg has also announced a package of reforms intended to improve rail safety while regulators try to strengthen safety rules.