A Closer Look at the Acute Air Quality Impacts and Human Health Risks of Large Methane Events in New Mexico

In August 2026, the New Mexico Environment Department (NMED) proposed new rule 20.2.51 NMAC – Methane Abatement Rule – which aims to reduce methane emissions from oil and gas production by establishing a methane super-emitter program and mandating zero-leak process controllers. Uniquely, the proposed methane super-emitter program covers methane emissions events with emissions above 50 kg CH₄/hr, below the EPA’s threshold of 100 kg CH₄/hr. Given the US Environmental Protection Agency’s (EPA) recent rollback of its super-emitter program, understanding the potential public health implications of the proposed New Mexico rule at the state level is especially valuable to inform state and local decision-making. 

PSE Healthy Energy’s analyses of the local air quality and human health implications of large methane emissions events indicate that large methane emissions from oil and gas facilities co-emit benzene and other hazardous air pollutants, and therefore can impact local air quality and can pose health risks to nearby communities.

Here we share some key insights on large methane emissions events (here defined as emissions rate  ≥50 kg CH₄/hr) in New Mexico from PSE’s gas composition database and Methane Risk Map (MRM).

Methods 

We reviewed the 571 produced gas and 286 flash gas samples from oil and gas production facilities in New Mexico in the Permian Basin from our gas composition database to determine prevalence of hazardous air pollutants.  Next, we summarized the estimated air quality impacts and human health risks of large emissions events (here defined at emissions rate  ≥50 kg CH₄/hr) modeled on the Methane Risk Map. To date, we have modeled 728 large methane emissions events that took place in New Mexico between 2019 and 2026. Motivated by the fact that NMED’s proposed methane super-emitter program defines super-emitters as methane emissions of at least 50 kg CH₄/hr,  we also conducted a subanalysis of the 108 events on the MRM with emissions rates between 50 and 100 kg CH₄/hr. The MRM allows users to compare modeled pollutant concentrations to acute health benchmarks, namely the California Office of Environmental Health Hazard Assessment (OEHHA) acute Reference Exposure Level (aREL) of 8 ppb and the Texas Commission on Environmental Quality (TCEQ) Effects Screening Level (ESL) of 53 ppb; the analysis presented here uses the CA OEHHA aREL. 

Takeaways for New Mexico

• Benzene, a known human carcinogen, and other hazardous air pollutants are almost always (>99% of 857 samples) detected in produced gas and flash gas from oil and gas facilities in New Mexico.
• Of the 728 large New Mexico events analyzed, 30% (216 events) had estimated outdoor benzene levels that exceeded the CA OEHHA aREL over at least one square mile.
  • Of the 108 events with emissions rates between 50 and 100 kg CH₄/hr, about 13% (14 events) had estimated outdoor benzene levels that exceeded the CA OEHHA aREL over at least one square mile.
• Of the 728 large New Mexico events analyzed, about one twentieth (37 events) potentially exposed at least 100 people to outdoor benzene levels exceeding the CA OEHHA aREL.
  • Of the 108 events with emissions rates between 50 and 100 kg CH₄/hr, all had modeled outdoor benzene levels that exceeded the CA OEHHA aREL, and one of these events east of Loving, NM potentially exposed over 100 people to such an exceedance.

Our review of New Mexico-specific natural gas composition data indicates that nearly all methane emissions from oil and gas facilities in New Mexico co-emit hazardous air pollutants, most notably benzene, a known human carcinogen. Methane emissions from oil and gas production overlapping or near population centers can expose populations and sensitive facilities to acute benzene levels and associated health risks. Events in the 50–100 kg CH₄/hr emissions range that fall below the cutoff of the EPA’s rescinded super-emitter program can also impact local air quality and increase benzene exposure in nearby communities. Therefore, New Mexico’s proposed rule to mitigate large methane emissions events of 50 kg CH₄/hr or higher can improve local air quality and protect public health.

The Methane Risk Map will be updated as new emissions events occur, and the tool is freely available to anyone who would like to track air quality impacts and human health risks from methane emissions in their area.

This research is part of PSE Healthy Energy’s Methane + Health Initiative, a multi-year research initiative to improve the scientific and public understanding of the link between methane emissions, air pollution, and public health.