New Ohio EPA Explosive Gas Monitoring Rule Promulgated


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New Ohio EPA Explosive Gas Monitoring Rule Promulgated

By: Steve Williamson, CPG

On October 21, 2020, the Division of Materials and Waste Management of the Ohio Environmental Protection Agency (Ohio EPA) announced that the proposed explosive gas rule,  for municipal solid waste landfills was filed with the Joint Committee on Agency Rule Review (JCARR).  Landfill gas is a natural by-product of the anaerobic decomposition of organic waste in a landfill.  The composition, quantity and rate of landfill gas generation are dependent on the types of waste that are decomposing and the level of microbial activity in the waste.  The production of landfill gas creates positive pressure with the landfill that forces the gas to migrate. Rule 3745-27-12 of the Ohio Administrative Code (OAC), first enacted in 1988, sets out the requirements for monitoring explosive gas migration at solid waste landfills. The proposed rule submitted to JCARR is substantially different from the 1988 rule. Because more than 50% of the rule was amended, the current rule is being rescinded and the new rule is being promulgated. As such, determining what changes were made to the rule is somewhat problematic. However, these are some of the changes that we see in the proposed rule:

  • Changes to the applicability of the rule, excluding solid waste landfill facilities that have an occupied structure within 1,000 feet of the limits of solid waste placement and were previously licensed between July 1, 1970 and May 31, 1988 unless they have received a notification from Ohio EPA that they are subject to the rule.
  • A requirement that all solid waste landfill facilities subject to the rule prepare an explosive gas monitoring plan (EGMP) on forms prescribed by the director. The director can require the preparation and submittal of a new or revised EGMP, including facilities that already have an approved EGMP. This is to ensure all EGMPs statewide are current and appropriately designed for the effective monitoring and managing explosive gas migration.
  • Language recognizing that the director may require previously excluded landfills to manage and remediate explosive gas migration towards occupied structures.
  • Requirements regarding the design, placement, and construction of explosive gas monitoring probes and alternative monitoring devices. The design of explosive gas probes includes the requirement that they be fully screened throughout the depth of waste placement. If there are multiple significant zones of saturation (SZSs), the director may require that multiple probes screened at each SZS be installed.
  • Language requiring explosive gas monitoring (probe installation and sampling) within 180 days of the discovery of new structures constructed within 1000 feet of the horizontal limits of solid waste placement.
  • Language regarding the explosive gas meters used for monitoring:
    • Detection limit (i.e., less than 1% methane by volume)
    • Calibration gas concentration to be between 1% and 5% methane by volume, or as specified by the manufacturer
    • Management of explosive gas alarms in structures
  • Provisions allowing the director to require the frequency of explosive gas monitoring

When this rule becomes effective, in accordance with Rule 3745-27-12(F), applicable landfills that are operating on the effective day of the rule must submit an EGMP concurrent with a request to alter an effective EGMP or at the same time as the ten-year update schedule. Solid waste landfill facilities that ceased operation prior to the effective date of this rule must submit an EGMP that complies with this rule no later than 270 days after the effective date of the revised rule or not later than 270 days after receipt of a notification from Ohio EPA that these rules apply to their facilities.

Published in October 2020 Focus on the Environment Newsletter


Steve Williamson is a Senior Scientist with Cox-Colvin & Associates, Inc. He holds a BS degree in Environmental Health and an MS degree in Hydrogeology from Wright State University. Mr. Williamson has over 30 years' experience working on brownfields, solid and hazardous waste, and groundwater contamination projects in Ohio and the Midwest.