A Texas waste hauling company that is already facing civil charges for a March accident that spread toxic drilling waste along a rural road could also be facing criminal charges.

Karnes County Sheriff Dwayne Villanueva said he will ask county prosecutors to file a criminal complaint against On Point Services LLC after the Texas Commission on Environmental Quality (TCEQ) and the Texas Railroad Commission close their civil cases against the company.

"We are prepared to ask the district attorney's office to review the case for action," Villanueva said. "There are two different levels of enforcement here: the civil by the state and the criminal by the county."

The incident occurred March 10 when investigators say 1,260 gallons of liquid waste from an On Point truck coated eight miles of roadway near the rural communities of Falls City and Hobson. Roads were closed for three days and the Texas Department of Transportation conducted a costly cleanup.

The incident highlights the growing problem of how to dispose of the billions of gallons of contaminated fluids left over from the nation's hydraulic-fracturing or fracking boom. Drilling waste typically includes toxic chemicals, oil, metals shavings, and naturally occurring radioactive materials. It's usually hauled to various sites so it can be injected into the ground in disposal wells, recycled, pumped into huge open pits to evaporate or sprayed on top of the earth in sprawling waste fields.

On Point, which is based in Falfurrias, Texas, failed to contain the spill, respond to the spill and inform authorities of the spill, according to the TCEQ notice of violation.

"Due to the apparent seriousness of the alleged violations, formal enforcement action has been initiated, and additional violations may be cited upon further review," according to the violation notice signed by Cameron Lopez, manager of TCEQ's Region 13 San Antonio Waste Section. "We encourage you to immediately begin taking actions to address the outstanding alleged violations."

The TCEQ told On Point to submit a written plan describing procedures to prevent future spills. It also directed the company to do a better job of maintaining its equipment and training its employees.

The Railroad Commission is seeking to sanction On Point for allegedly violating state water protection and leak rules, said Ramona Nye, a commission spokeswoman.

"Transport vehicle was not operated in a manner to prevent spillage or leakage of oil and gas waste during transportation," according to the Railroad Commission's letter to On Point.

On Point now has an opportunity to dispute the charges. The process could take months and, if the agencies' findings stand, could lead to fines for On Point.

A representative for On Point hung up when asked for comment. But in an earlier interview, owner Winfred Stanfield suggested that his company might not have been responsible for the spill, saying five companies had been implicated in the incident.

When Karnes County sheriff's investigators confronted Stanfield with the evidence, Stanfield blamed the driver, according to the sheriff's investigative report. Stanfield said the driver was "not fully competent."

If not for surveillance video given to the Sherriff's Department by a citizen, the 18-wheel tanker truck responsible for the dumping may have disappeared into the night. Using the video, the department narrowed the possible suspects to two companies. After one of the companies provided GPS data showing that its truck didn't travel the spill route, the investigation turned to On Point.

Sheriff's investigators learned that an On Point tanker left a drilling site loaded with drilling fluid, according to the department's report, which the TCEQ and the Railroad Commission credit as the basis for their recent actions. Records show the tank was empty when it arrived at a facility where tankers are cleaned out, according to the report.

The driver told sheriff's investigators that the valve of the back of his tanker sometimes leaked. He said he couldn't remember whether he had checked the valve on the night the incident occurred.