NOVEMBER 2009

Concerns over explosive situation bring agreement to investigate landfill methane

Concern that elevated underground methane levels could lead to an explosion has prompted St. Bernard and Ohio Environmental Protection Agency (EPA) to reach an agreement about how the city will investigate and correct problems at its closed landfill.

The landfill stopped receiving waste in the 1970s and closed in 1985.

Under state law, St. Bernard is required to monitor the landfill’s boundaries for methane gas produced by waste that moves underground between soil particles and along utility pipes. Ohio EPA is concerned that methane is moving underground from the landfill and may collect in low areas or people’s homes at levels capable of igniting or exploding.

Methane levels have fluctuated, but they have since returned to unacceptably high levels. Based on these results, the city needs to perform additional remedial measures in order to minimize landfill gas production.

Landfill owners or operators must monitor methane gas levels at their property boundaries and take action to protect occupied structures, such as homes, that are located within 1,000 feet of landfill waste placement. In 2008, St. Bernard reported that 9 homes are within 200 feet of waste. Two hundred thirty-four occupied structures are within 1,000 feet of waste.

Since 2000, the city has monitored methane gas levels, reported gas level exceedances, and installed remedial measures. Despite these measures, exceedances continue to occur. In 2003, Ohio EPA ordered St. Bernard to abate or minimize the formation or migration of explosive gas from the landfill. The city was required to develop, submit and implement a plan to remediate explosive gas migration. The city also was required to revise its explosive gas monitoring plan. While methane levels initially dropped, they have returned to unacceptably high levels.

Ohio EPA and St. Bernard have agreed that the city will do additional work to bring levels down.

The city has agreed to:

  • Delineate exactly where waste explosive gas has migrated; this will involve drilling monitoring probes in people’s yards;
  • If waste is found beyond the area in which it is believed to be, additional work must be done while performing the gas delineation;
  • Propose remedial measures to abate or minimize explosive gas levels;
  • Convert its current gas extraction system into a continuously operating, automated system;
  • Revise its gas monitoring plan which may include additional monitoring probe installation;
  • Unless damaged or inaccessible, leave current and future monitoring probes in place; and
  • Install gas alarms in homes where property owners authorize access.