Fire Prevention and Mitigation

Protecting Communities from Preventable Disasters

The Problem: Landfill Fires Are Preventable Disasters to Communities 

Across the United States, landfills are increasingly becoming sources of dangerous heat, toxic pollution, and uncontrolled methane emissions, exposing major gaps in current regulatory systems. A Bloomberg news investigation highlights a pattern of elevated-temperature landfills, underground fires, and large methane releases that often persist for months or years with limited government oversight.

Landfills are complex, poorly monitored systems where conditions can deteriorate rapidly. Subsurface reactions and smoldering fires can generate extreme heat, damage gas collection systems, and release a mix of methane and hazardous air pollutants. Once these events begin, they are notoriously difficult and expensive to control, making prevention and early detection critical.  Communities living near landfills bear the brunt of these failures, including toxic exposures, odors, evacuations, and long-term health concerns.  Landfill emissions include not just methane, but also hazardous air pollutants linked to cancer and respiratory harm, compounding the risk.

Landfill fires and their harms are preventable but federal regulations are not designed to detect or respond to these problems in real time. Monitoring is often limited, infrequent, and reliant on outdated methods, meaning major emission events can go unnoticed or unaddressed. Even when warning signs like rising temperatures or gas imbalances are detected, rules often do not require timely corrective action, allowing problems to escalate. Yet available technology and practices now makes proactive, real-time oversight possible - if regulations are fixed.  Preventing them is far cheaper, safer, and more effective than trying to put them out after the fact.

How Landfill Subsurface Elevated Temperature Events and Subsurface Fires Happen

Subsurface Elevated Temperature (SET) events, also referred to as elevated temperature landfills (ETLFs),  are now recognized by the U.S. EPA as a distinct and growing problem across the country. EPA’s 2023 research found that these exothermic reactions are caused not by traditional flames but by anaerobic chemical reactions that can reach temperatures of 180 °F (82 °C) or more, destroying liners, gas pipes, and collection systems. This spells catastrophe for controlling harmful emissions. 

Experts Jafari, Thalhamer, and Stark (2025) warn that the “watch” threshold for an elevated temperature event begins at 131 °F (55 °C) and that by 140 °F, plastic pipes and HDPE liners begin to deform. Once temperatures exceed 170 °F, pyrolysis and smoldering reactions accelerate; above 212 °F, water expands over 1,700 times, driving pressure, cracking, and boosting emissions.

Once initiated, SET events alter landfill gas chemistry: methane declines, carbon dioxide and carbon monoxide spike. Hydrogen - which has no business being present in a landfill - may reach over 50 percent by volume. These are the key chemical indicators that should serve as  early diagnostic markers for regulators, but, sadly, communities are paying the price for wholly inadequate regulations. 

The EPA and independent researchers have identified leading triggers:

  • Over-pulling on gas collection wells, which draws oxygen, a key ingredient to trigger fires or elevated temperatures, into the waste mass.

  • Poor sealing or cracks in the landfill cover, which lets oxygen into the landfill, which is a key ingredient in fires. 

  • Reactive materials in the landfill like slag or incinerator ash, or cover materials that use ashes or slags - these materials can catalyze exothermic reactions.

  • Leachate recirculation by the landfill operator, which adds moisture inside the landfill and accelerates biochemical reactions.

Why Current Regulations Fail to Prevent Landfill Fires

Despite clear scientific warning signs and decades of experience, today’s federal landfill fire regulations, again, implemented by states, fundamentally misaligned with how subsurface fires actually start and spread. In practice, the rules allow dangerous conditions to persist unchecked until a full-scale disaster is already underway.

  • Monitoring Without Mandatory Action Is a Public Safety Failure: Federal landfill rules require operators to measure temperature, oxygen, and nitrogen at wellheads — but they do not require corrective action when those alarms go off. Operators can document rising temperatures, increasing oxygen intrusion, and deteriorating gas chemistry month after month without being obligated to change operations. This is the regulatory equivalent of installing a smoke detector that’s allowed to blare indefinitely — with no requirement to investigate, fix wiring, or put out the fire.

  • Fire-Prevention Standards Were Weakened, Not Improved: EPA’s original landfill standards recognized that subsurface fires begin far earlier than visible flames. The 1996 federal rules required corrective action at 131 °F, with limits on oxygen (5%) and nitrogen (20%) as early indicators of air intrusion and combustion risk. Over time, those protections were quietly dismantled: The temperature threshold was raised to 145 °F, and Oxygen and nitrogen limits were eliminated entirely. Corrective action requirements were stripped out, leaving monitoring without enforcement. These changes were not driven by new science — they were driven by industry pressure. The result is a regulatory system that tolerates known fire conditions instead of preventing them.

  • Landfill Operators Are Allowed to Choose the Weaker Standard: Under current federal rules, landfill operators can elect to comply with the more lenient NESHAP provisions instead of stricter NSPS or Emission Guidelines requirements. In practice, this means: Operators can lawfully ignore early-warning thresholds, and the most protective standards are optional.

  • Wellhead Monitoring Misses the Real Heat: Most regulations rely on surface-level wellhead readings, even though regulators and EPA researchers have repeatedly documented that subsurface temperatures can be 50 °F or more hotter at depth. At sites like the Chiquita Canyon Landfill in Los Angeles County, downwell temperatures exceeded 190 °F while surface readings appeared only moderately elevated. Without required downwell monitoring, regulators are effectively blind to the most dangerous conditions — the reactions happening deep in the waste mass where fires originate.

The Rules React to Disasters Instead of Preventing Them: Once a subsurface fire or elevated temperature landfill (ETLF) is established, it can burn or smolder for years. Suppression efforts are costly, disruptive, and often only partially effective. Yet current regulations are structured around detecting problems late, allowing prolonged non-response, and escalating what landfills are required to do only after irreversible damage has occurred. This approach is like playing Russian Roulette, and guarantees higher costs, greater emissions, and more harm to surrounding communities.

Communities Pay the Price for Regulatory Gaps

While operators are allowed to “monitor and wait,” nearby residents bear the consequences: toxic air pollution, evacuation orders, school closures, property damage, and long-term health risks. These are not hypothetical harms — they are already playing out across the country.

Landfill fires are crises for the people who live nearby. When landfills overheat or ignite underground, surrounding communities are exposed to toxic air pollution, persistent odors, evacuation orders, and prolonged uncertainty that can last for years. Investigative reporting by Bloomberg News has shown that “hot” landfills are becoming more common nationwide, driven by a combination of climate change, larger waste volumes, delayed gas collection, and outdated operating rules. These events disproportionately affect low-income communities and communities of color, many of whom already shoulder cumulative pollution burdens and have limited ability to relocate or protect themselves.

Once a landfill enters an elevated temperature or smoldering state, nearby residents often experience:

  • Chronic exposure to benzene, hydrogen sulfide, vinyl chloride, and other toxic co-pollutants

  • Headaches, nausea, respiratory symptoms, and stress-related health effects

  • Disruptions to daily life, including school closures, missed work, and declining property values

Case Study: Chiquita Canyon Landfill, California

Chiquita Canyon Landfill, owned by Waste Connections, is a clear example of how weak fire-prevention rules translate into real harm for real people.

Located in the communities of Val Verde and Castaic in Los Angeles County, Chiquita Canyon Landfill is experiencing a prolonged subsurface elevated temperature event that regulators and operators struggle to control. What began as internal overheating has escalated into a years-long crisis affecting thousands and thousands of residents.

What Went Wrong

  • Early warning signs were present: rising temperatures, abnormal gas chemistry, and declining methane levels consistent with subsurface reactions.

  • Regulatory thresholds were too high and too slow: By the time of action to try to address the problem, heat had already migrated deep within the waste mass.

  • Monitoring focused on the surface: Wellhead readings failed to reflect much higher temperatures deeper underground, delaying recognition of the severity.

  • Corrective action was reactive, not preventative: Controls were layered on only after the fire was well established.

Suffering Residents

Within 1 mile of the landfill, 67% of residents are Black, Indigenous, or People of Color - showing that communities of color are disproportionately exposed. Residents face ozone levels worse than 96–97% of the U.S.—meaning they breathe more ozone pollution than almost anyone in the country.  

Chiquita Canyon Landfill is far from rural. In addition to homes, the landfill is located within just miles of schools, parks, and other community gathering spaces.  Within five miles of the landfill you’ll find a range of early-childhood and K-12 schools - including Val Verde Head Start Preschool, Live Oak Elementary, Castaic Elementary, Castaic Middle School, SCVI,  Montessori of Valencia, Legacy Christian Academy, Trinity Classical Academy, Sunshine Learning Centers, and Montessori of Stevenson Ranch - serving hundreds of students across preschool through middle school levels. Trinity Classical Academy alone enrolls over 500 students from TK through 12th grade. This means children are living, learning, and playing just minutes from the landfill, facing daily exposure to its pollutants.

Residents reported:

  • Persistent, noxious odors forcing families to seal homes or temporarily relocate

  • Physical symptoms including headaches, nosebleeds, nausea, skin irritation, eye irritation, ringing in the ears, and breathing difficulties

  • Anxiety, depression, sleep disruption, and loss of trust in public institutions

Meanwhile, Carbon Mapper found frequent and significant methane leaks at the Chiquita Canyon Landfill - 153 methane plumes (bursts of methane pollution) were detected on 15 different days out of 30 days studied. That means methane was escaping from the landfill on half of all observation days. When leaks were happening, the landfill was releasing an average of 595 kilograms of methane every hour—a large amount of climate-warming pollution.

Key Regulatory Provisions Needed for Fire Prevention

States can update their state requirements to address the many gaps in the federal requirements that some landfills must operate under.  States should treat landfill fire prevention as a basic public safety obligation by the landfill operator.

Early Testing Before Connection
 CARB’s 2025 Landfill Methane Rule (LMR) mandates earlier installation and operation of gas-collection infrastructure in new waste areas and continuous wellhead monitoring to avoid overdrawing and air intrusion. States can mirror this: require pre-connection pressure testing and phased tie-ins once positive pressure is verified.

Continuous Downwell Temperature Monitoring
 At Chiquita Canyon Landfill, CalRecycle investigators documented downwell temps > 190 °F even as wellhead readings stayed near 120 °F.  That’s because those wellhead readings were at the surface - downwell is where you can actually begin to understand what is truly going on. EPA’s 2024 white paper on Increasing LFG Collection Rates highlights that downwell sensors are needed to give “essential early-warning diagnostics” for localized reactions. State regulations should require continuous or representative downwell probes with action thresholds at 110 °F (watch) and 140 °F (critical).

Action Thresholds for Temperature and Oxygen
 California’s AB 28 (2025) codifies the needed escalating response tiers, to prevent landfill subsurface fires. If the temperature is: 

  • ≥ 131 °F for 60 days → require a collection-system and cover assessment.

  • ≥ 146 °F → require a mandatory multi-agency corrective-action coordination.

  • ≥ 170 °F → enforcement penalties up to $1 million per week until temperatures subside.

Rapid-Response Protocols
 When temperatures exceed 140 °F, the landfill must take action including: 

  • Stop vacuum draw on affected wells.

  • Install additional temperature and CO sensors in adjacent wells

  • Map heat migration via gas-composition and subsurface probes.

  • Submit a corrective-action plan within 30 days, publicly posted.

Costs and Benefits

  Preventing landfill subsurface fires is dramatically cheaper than fighting them. According to EPA’s 2022 Maryland Technical Support Document, installing or modifying a GCCS typically costs $1–3 million with $150,000–$400,000 in annual O&M. It costs a few thousand dollars per well for temperature probes and monitoring equipment. In addition, upgrading state regulations to include continuous monitoring and early-action frameworks means using equipment already standard in the industry. 

The cost of inaction is not theoretical: landfill fire events have bankrupted operators, displaced families, and polluted entire regions. Preventing even one SET event avoids tens of millions in damage—as Missouri’s landfill fire, with over $450 million in losses, demonstrated.

Myth-Busting

Industry Claim: Higher operating temperatures improve gas capture efficiency.


Fact: That’s like revving an engine without oil: it might run hotter at first, but it destroys itself and fails faster. Overdrawing the gas system introduces oxygen, drives combustion, and accelerates chemical reactions. Methane capture drops sharply once materials heat up and degrade.

Industry Claim: Our landfill operates fine at an elevated temperature.


Fact: