EPA Issues Final Denial of Petition to Revise the RCRA Corrosivity Hazardous Characteristic


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EPA Issues Final Denial of Petition to Revise the RCRA Corrosivity Hazardous Characteristic

By: George Colvin, CPG, CHMM

Under subtitle C of RCRA, the EPA has developed regulations to identify solid wastes that must then be classified as hazardous waste.  Corrosivity is one of four characteristics of wastes that may cause them to be classified as RCRA hazardous waste.  The agency defines which wastes are hazardous because of their corrosive properties at 40 CFR 261.22.  Under these regulations, aqueous wastes having a pH 2 or lower, or 12.5 or higher, are regulated as hazardous waste. Liquid wastes that corrode steel above a certain rate are also classified as corrosive under RCRA. A solid waste that exhibits the characteristic of corrosivity carries the EPA Hazardous Waste Code of D002.

On September 8, 2011, the non-governmental organization Public Employees for Environmental Responsibility (PEER) and an EPA employee submitted a rulemaking petition to the EPA seeking changes to the current regulatory definition of corrosive hazardous wastes under RCRA.  The petition sought two specific changes to the 40 CFR 261.22(a) definition of a corrosive hazardous waste:

  • Revision of the pH regulatory value for defining a waste as corrosive hazardous waste from the current pH 12.5 or higher, to pH 11.5 or higher, and
  • Expansion of the scope the corrosivity regulation to apply to non-aqueous wastes in addition to the aqueous wastes addressed by the current regulation.

The petition argued that the regulatory pH value should be revised to pH 11.5 because information supporting this value was, in the petitioner’s view, inadequately considered in developing the original regulations and because the lower value is widely used as a threshold for identifying corrosive material outside of RCRA.  The petition further argued that corrosive properties of inhaled concrete dust, for example, caused injury to first responders and others in the World Trade Center disasters on September 11, 2001, and that such non-aqueous dusts should be regulated as corrosive hazardous waste under RCRA.

The Agency published for public comment its tentative decision on April 11, 2016 (81 FR 21295), proposing to deny both requested revisions to the corrosivity characteristic regulation sought by the petitioners.    In the recent June 15, 2021 Federal Register notice (86 FR 31622), the EPA responds to the 29 public comments received on the tentative denial and takes final action to deny the petition.  Through the June 15 notice, the Agency concluded that because the available information does not support revision of the RCRA corrosivity characteristic regulations sought by the petitioners, such revisions are unwarranted.

If, based on comments, EPA had decided to reverse its tentative decision and propose new rules to lower the pH standard to 11.5, the action would have broaden the scope and volume of materials meeting the corrosive criteria.  Ammonia, for instance, with a pH of 11.6 would be characterized as a corrosive waste and subject to the applicable RCRA requirements.  The request to expand the RCRA corrosivity definition to include nonaqueous wastes could, among other things, have resulted in large volumes of lime-stabilized waste, which when treated are otherwise non-hazardous, being classified as hazardous because of their pH. 

On a separate note, given the nearly 10-year period it took to complete this final denial of a relatively simple revision to a hazardous waste characteristic, it is hard to imagine that EPA could find a way to designate per- and polyfluoroalkyl substances (PFAS) as hazardous waste under RCRA (as some have requested) in a reasonable time frame.


George H. Colvin is a hydrogeologist with over 30 years of consulting experience. Much of his experience has focused on RCRA Corrective Action, RCRA closure, and groundwater investigation, monitoring, and cleanup. He holds a BS in Geology from Ohio University and MS in geology and hydrology from Vanderbilt University. He is a Certified Professional Geologist with the American Institute of Professional Geologists, a registered geologist in Kentucky, Pennsylvania, and Tennessee, and a Certified Hazardous Materials Manager.