"The program is basically a paper tiger," said Mario Salazar, a former senior technical advisor to the Environmental Protection Agency who worked with its injection regulation program for 25 years. While wells that handle hazardous waste from other industries have been held to increasingly tough standards, Salazar said, Class 2 wells remain a gaping hole in the system. "There are not enough people to look at how these wells are drilled … to witness whether what they tell you they will do is in fact what they are doing."
Thanks in part to legislative measures and rulemaking dating back to the late 1970s, material from oil and gas drilling is defined as nonhazardous, no matter what it contains. Oversight of Class 2 wells is often relegated to overstretched, understaffed state oil and gas agencies, which have to balance encouraging energy production with protecting the environment. In some areas, funding for enforcement has dropped even as drilling activity has surged, leading to more wells and more waste overseen by fewer inspectors.
"Class 2 wells constitute a serious problem," said John Apps, a leading geoscientist and injection expert who works with the U.S. Department of Energy's Lawrence Berkeley National Laboratory. "The risk to water? I think it's high, partially because of the enormous number of these wells and the fact that they are not regulated with the same degree of conscientiousness."
In response to questions about the adequacy of oversight, the EPA, which holds primary regulatory authority over injection wells, reissued a statement it supplied to ProPublica for an earlier article in June.
"Underground injection has been and continues to be a viable technique for subsurface storage and disposal of fluids when properly done," a spokesperson wrote. "EPA recognizes that more can be done to enhance drinking water safeguards and, along with states and tribes, will work to improve the efficiency of the underground injection control program."
Some at the EPA and at the Department of Justice, which prosecutes environmental crimes, say the system's blind spots suggest that many more violations likely go undiscovered – at least until they mushroom into a crisis.
That's what happened at Rosharon.
The accident prompted the EPA to examine what else had been dumped at the site, ultimately exposing a scheme by a company that was not involved in the explosion, Texas Oil and Gathering, to pass off deadly chemicals from a petroleum refining plant as saltwater from drilling.
The switch saved the company substantial fees by allowing it to dispose of the material in a Class 2 well, instead of a more stringently controlled well for hazardous waste, federal investigators said.
Texas Oil and Gathering's owner and operations manager were convicted of conspiring to dump illegal waste and violating the Safe Drinking Water Act. Both declined to comment for this article.
Texas officials acknowledged that they had not looked beyond the paperwork submitted by the operators using the well. The delivery trucks weren't inspected; the wastewater was not sampled.
"Staff had no reason to believe at the time that such testing was necessary at this facility,'' Ramona Nye, a spokeswoman for the Railroad Commission of Texas, which regulates the oil and gas industry activity in the state, wrote in an email. "The likelihood of unpermitted material being disposed of is low.''
William Miller, the EPA's chief investigator on the case, points out that the only reason anyone was held accountable for injection-related violations was because the site blew up.