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Washington State Authorizes Drone for Methane Emissions Monitoring in New Landfill Methane Emissions Rule!

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: 

  • SEM inspection performed by a field technician traversing in a serpentine path with no more than 25-ft spacing between the inspection paths.

  • Instantaneous and integrated surface emissions reporting. 

  • SEM operations restricted to a maximum average and instantaneous wind speed and cannot be performed earlier than 72 hours after precipitation.

While the new rule will drive greater accountability for methane emissions, it will also lead to increased labor costs and technicians' exposure to hazards by increasing their inspection time threefold. Washington has alleviated these concerns by allowing the use of a drone to perform work that would otherwise be performed manually. The drone (an unmanned aerial system referred to as the SnifferDRONE™) performs the inspection 50% faster, thus reducing technician's exposure to hazards, while improving the effectiveness of detecting methane emissions and their leak sources. 

The US EPA was the first to approve the use of an unmanned aerial system (UAS) for this purpose as outlined in Other Test Method 51 (OTM-51). Washington has integrated OTM-51, with modifications, in their new rule. The method, utilizing the UAS, provides confidence in inspection via greater process control, data management, and professional reporting.    

Industry leaders in Washington began using the SnifferDRONE for landfill emission monitoring in 2023. These early adopters recognized the opportunity to improve the environment and their operations. We congratulate these leaders for their vision and thank them for making a difference.

We look forward to continuing our work in the state and beyond to improve the methods for detecting and accounting for landfill methane emissions.


About Sniffer Robotics 

Sniffer Robotics is a leading environmental technology enabled services firm serving the waste, natural gas, and agriculture industries throughout the United States. Sniffer's methods, automation tools, and software solutions help improve their customers' compliance standing and operational performance while benefiting the environment. Sniffer was recognized as one of the top 250 Greentech Companies in America by TIME and Statista. Learn more at 

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