Q&A
Question Overview
  • Is Bridgeton Landfill safe?
  • Why is there odor?
  • What is leachate?
  • How do I report an odor concern?
  • What is being done to manage the odor?
  • When will the odor go away?
  • Is the subsurface reaction a fire?
  • Is the reaction moving into the "neck"?
  • Is the reaction at risk of reaching West Lake Landfill?
  • Could the reaction break through the ground surface?
  • Why can’t the reaction be extinguished?
  • What role do local first responders play at the site?
  • When will the isolation barrier be built?
  • What is Bridgeton Landfill’s relationship to West Lake Landfill?
Is Bridgeton Landfill safe?
Yes. State regulators and public health officials confirm that the odor does not present a risk to public health or safety.

Air monitoring data is collected twice daily at 13 locations around the perimeter of the site, as well as during weekly tests. The Missouri Department of Natural Resources (MDNR) analyzes data with the Missouri Department of Health & Senior Services. This data is available on the Air Monitoring page of this website, as well as on the MDNR website.
Why is there odor?
A heat-producing reaction deep within the landfill is causing trash to decompose at an accelerated rate. This produces more gas and liquid than normal, and has been the primary source of odor. The reaction presented a highly-complex gas and liquid management challenge, requiring sophisticated extraction, pretreatment and disposal infrastructure, as well as a site management team with considerable expertise.
What is leachate?
Leachate is the liquid byproduct of decomposing waste. It is found in all landfills.
How do I report an odor concern?
By visiting the Missouri Department of Natural Resources website at: http://www.dnr.mo.gov/bridgeton and submitting an odor concern form. You can also access the odor concern form on the Air Monitoring page of this website.

In April 2014, Bridgeton Landfill and the Missouri Department of Natural Resources introduced real-time odor response capabilities for concerns submitted online. Today, nine out of ten odor concerns filed are determined to have originated from a non-landfill source.
What is being done to manage the odor?
We have invested approximately $125 million in odor control and environmental remediation, including a leachate pretreatment plant, upgraded gas and leachate extraction systems, an upgraded flare system to destroy captured gas, a synthetic liner over the South Quarry and a portion of the North Quarry, and a waste water conveyance line that connects with the Metropolitan St. Louis Sewer District. We also established monitoring and real-time odor complaint response capabilities with the Missouri Department of Natural Resources. Today, more than three out of four odor complaints are determined to have originated from non-landfill sources.
When will the odor go away?
We believe the worst of the odor is in the past. We brought considerable expertise, resources and capabilities to bear to control odors, and a recent order of the Circuit Court of St. Louis County finds that substantial work has been completed on the site. While we cannot predict with certainty the life-span of this heat-producing reaction, we are leveraging our experience from operating roughly 300 active and closed landfills across the country to further reduce and control any residual odor emanating from the site.
Is the subsurface reaction a fire?
No. A fire requires oxygen. This a heat-producing reaction occurring in the South Quarry, deep below the surface in an environment that is naturally deprived of oxygen due to both depth and the normal decomposition of waste. In this circumstance, the best practice is to manage the reaction by extracting energy, or heat. This restricts the reaction’s capacity to move and produce additional odor-causing gas and liquid.
Is the reaction moving into the "neck"?
No. At this time, there is no indication that the reaction is moving into the "neck" area, between the North and South Quarries. The Landfill team relies upon a comprehensive set of data when determining the location and movement of the reaction, including carbon monoxide levels, elevated subsurface temperatures and higher than normal surface settlement. Despite assertions about isolated data points made by a consultant to the Missouri Department of Natural Resources, the totality of data continues to confirm that the reaction is in the South Quarry, moving away from the "neck" and the adjacent West Lake Landfill.
Is the reaction at risk of reaching West Lake Landfill?
No, not at this time. All data indicates that the reaction is occurring in the South Quarry and it is moving slowly to the south, away from the adjacent West Lake Landfill.

The Landfill team has installed more than 200 gas extraction and interceptor wells, as well as more than a dozen temperature monitoring probes and alternative technologies to extract heat from the subsurface. This and other key infrastructure enables to the Landfill team to manage the reaction. In addition, the team closely monitors and evaluates extensive amounts of data on carbon monoxide levels, higher than normal subsurface temperatures and surface settlement in coordination with the Missouri Department of Natural Resources. The reaction is not, nor has it ever been, close to the original response triggers established with the State of Missouri.
Could the reaction break through the ground surface?
No. Based on data, science and experience, we do not believe this is plausible. In addition, the reaction is occurring at a depth of approximately 150 feet, beneath soil and waste and absent of oxygen. The reaction is in a managed state.
Why can’t the reaction be extinguished?
Fires are generally extinguished by oxygen deprivation or with water. This is a heat-producing reaction occurring at a depth of approximately 150 feet, where there is little-to-no oxygen present. The reaction may continue to generate higher than normal subsurface temperatures and carbon monoxide levels for years, as it continues to cause waste to decompose at an accelerated rate.
What role do local first responders play at the site?
The Landfill team recently announced an updated Incident Management Plan developed in coordination with local first responders. It is accessible on the Official Reports page of this website. The plan establishes roles and responsibilities for a coordinated response in the event of an incident. It also contemplates various incident scenarios and identifies onsite resources available for a coordinated response. In response to the plan, the Missouri Department of Natural Resources recently recognized the Landfill for its efforts to improve communication and coordination with local first responders, and expressed satisfaction with the plan. The Landfill team continues to meet, share information and coordinate regularly with local first responders.
When will the isolation barrier be built?
The public debate about an isolation barrier hypothesizes that heat from the subsurface reaction could reach radiologically impacted material buried in the adjacent West Lake Landfill, or that a second reaction could originate near radiologically impacted material.

There continues to be no health, safety or environmental reason to build a barrier. The U.S. Environmental Protection Agency (EPA) has said that West Lake Landfill is safe. The Missouri Department of Health & Senior Services has said there is no public health or safety risk at Bridgeton Landfill. In addition, it is highly-unlikely that the reaction which is occurring in one portion of the South Quarry, and is moving south — away from West Lake Landfill — will reverse direction and migrate vertically and laterally toward radiologically impacted material.

There is reason to debate whether a barrier is even necessary. Still, the Landfill team continues to work closely on barrier options with the EPA, who has assembled a team of experts that includes the U.S. Army Corps of Engineers and U.S. Geological Survey. The Landfill team has solicited input and perspective from important community partners, such as St. Louis International Airport, the Federal Aviation Administration and U.S. Department of Agriculture. In addition, the team has retained one of the foremost bird mitigation experts in North America to consult on the various barrier options.

If the EPA elects to install a barrier, it should be technically feasible, bring resolution to the matter within a reasonably fast time frame and satisfy legitimate Airport concerns regarding bird hazards to commercial aircraft.
What is Bridgeton Landfill’s relationship to West Lake Landfill?
The Bridgeton Landfill is adjacent to the West Lake Landfill OU-1, which is a designated EPA Superfund Site that contains low-level radiologically impacted material. Both sites were acquired as part of a much larger transaction in 2008. Detailed information about West Lake Landfill can be found at: http://westlakelandfill.com.