Last week, the Environmental Protection Agency (EPA) determined that oil and gas solid waste will remain exempt to federal rules governing the disposal of hazardous waste. This exemption was put in place by the 1980 "Bentsen Amendment” to Subtitle C of the Resources Conservation and Recovery Act (RCRA), and was revisited in 2019 following a lawsuit led by a group of environmental organizations. Under this exemption, waste from oil and gas exploration and production can be treated similarly to household waste—for example, it can be sent to a municipal landfill. The exemption was made before the onset of US shale development, which has experienced a boom over the last decade, changing the quantity and type of solid waste produced.
The EPA has decided to keep the exemption, deeming that existing state and federal programs are generally “adequate to control the wastes,” and also that the removal of the exemption would put constraints on Subtitle C facilities as well as the permitting process accompanying solid waste disposal, which could result in delays for oil and gas activities.
A few months ago, we contributed to a paper on the chemical composition of solid waste from 231 fracked wells in Pennsylvania. While this is a small sample of wells, it is the largest database on solid waste from shale wells compiled to date. Using company-submitted test results of the amount of chemicals that leach out of the solid ("leachate") we compared the lab tests to limits outlined in RCRA to determine toxicity. Having done this exercise, we know that EPA’s decision was a hard call to make. While most of the solid waste contains chemicals that are listed in RCRA as toxic, only a handful of the samples had leachate concentrations that would have exceeded RCRA toxicity limits. This was consistent with the finding in the EPA’s report that “there can be orders-of-magnitude variability in the composition of each waste type.”
There clearly exist dangerous outliers (which could compromise water quality), but in most cases, concentrations are below toxic levels. Eight of the 40 chemicals listed as toxic in RCRA were present in our samples, and two of these—barium and chromium—occasionally exceeded RCRA toxicity limits. The EPA’s report also notes high barium concentrations in the previous literature on shale waste and discusses the possibility that this could be from a commonly used drilling fluid additive, barite.
This type of situation is tricky to regulate, particularly if the toxic outliers are hard to detect. However, some states currently require shale developers to test the contents of waste streams for toxic chemicals prior to offsite disposal. In fact, we were only able to study these lab samples because firms in Pennsylvania must file an annual residual waste report, known as Form 26R, for each waste stream if they generate more than 2,200 pounds of residual waste in any given month from a well pad. Therefore, it may be reasonable to require the monitoring of all solid wastes and special treatment of the toxic outliers. Of the eight EPA-identified states that test waste before allowing “beneficial use” (e.g., in concrete or road application), only five test for barium, and three for chromium. We recommend that waste is tested for barium and chromium before being used.
Many states regulate solid waste streams, but do so in ways that are not consistent with one another. In particular, some require testing and others do not. To preclude operators shopping across state lines for the least stringent regulatory environment to dispose of their wastes, we think that there should be minimum guidelines applicable to all states.
RCRA requires that its regulations be reviewed and, where necessary, revised at least every three years. Until the next review, much more research on the composition of solid waste is warranted (research to date has focused on liquid waste). Research is also needed on the risk associated with aggregation of waste shipments in a landfill; even if each has low leachate concentrations, total concentrations could be significantly higher.
Finally, analyses of solid and liquid wastes would be made less costly by digital reporting. To study the lab samples, our coauthor Ziyan Chu drove to all the regional offices of the Pennsylvania Department of Protection to scan paper copies of lab reports. These then had to be deciphered and formulated into a unified database. Further research in this area would be facilitated by streamlining and digitizing waste reporting.