On May 13th, the Washington State Department of Ecology announced a new methane emission rule (Chapter 173-408 WAC) for active and closed solid waste (MSW) landfills in their state. All affected landfills must meet the requirements starting January 1, 2025.
While the requirements of the new rule are lengthy, and will impact many aspects of landfill operations, this announcement is narrowly focused on new requirements specific to surface emissions monitoring (SEM). Washington’s new requirements mirror those of California, Oregon and Maryland, requiring:
