Trump Administration Delays Fenceline Monitoring for Hazardous Air Pollutants
The Rollback of the HON Rule
On July 13, the administration announced a clawback of a rule, two days before it was set to go into effect. The regulation was designed to move the U.S. away from estimated emission calculations, which have been found to underestimate actual air pollution, toward continuous, real-time data collection at the perimeter of industrial facilities.
Under the timeline established in July 2024, regulated facilities were given two years to begin real-time and continuous “fenceline” monitoring of six hazardous air pollutants. The mandate required data collection to begin by July 15 of this year, with the resulting data becoming available to the public by July 2027. The administration’s announcement this week provides two-year extensions for 20 more facilities, including five located in Louisiana.
Impact on Louisiana’s Cancer Alley
The delay specifically affects residents in regions like Saint John the Baptist Parish in Louisiana, where the petrochemical industry is densely concentrated. Residents there describe cancer, adverse birth outcomes, and other reproductive harms that they worry may be linked to pollution from the fossil fuel industries in their backyards.
The revised HON rule included requirements for facilities to reduce emissions and take corrective actions if monitoring revealed pollutant levels exceeding standards. According to calculations from the Biden administration, the full implementation of these rules would have drastically lowered cancer risks and other health threats for communities living in these industrial zones.
Deregulatory Agenda and Implementation Timeline
The decision to grant extensions is part of a broader deregulatory agenda pursued by President Donald Trump. In 2025, President Donald Trump provided two-year extensions for implementing the rule for many facilities, including in Louisiana. This most recent move extends that grace period to further sites, effectively pushing back the date when communities will have transparent access to the chemical composition of the air they breathe.
The shift in policy represents a reversal of a transparency victory for environmental advocates who have fought for decades to replace theoretical emission models with empirical, real-time monitoring. The administration’s current position maintains these extensions for the identified facilities, leaving the timeline for full HON rule compliance unresolved.
