The U.S. Environmental Protection Agency intends to classify the entire U.S. Virgin Islands as “attainment/unclassifiable” under its revised annual standard for fine-particle pollution, a preliminary decision that differs from the territory’s recommendation. Territorial officials had requested “unclassifiable,” citing insufficient monitoring data. The designation concerns a specific outdoor-air standard, rather than a finding that every community is free of pollution.
EPA Region 2 Administrator Michael R. Martucci outlined the intended designation in a September 30, 2026 letter to Governor Albert Bryan Jr., posted on the agency’s territory-specific webpage as part of its October 2 rollout. The proposal covers the whole territory. Department of Planning and Natural Resources Commissioner Jean-Pierre L. Oriol’s January 24, 2025 recommendation had cited insufficient data from the Virgin Islands’ PM2.5 monitoring network during the period considered.
In everyday terms, attainment means an area meets the applicable air-quality standard, while nonattainment means it violates the standard or contributes to a nearby violation. Unclassifiable means the available information is insufficient to decide. EPA uses the combined attainment/unclassifiable category for areas it determines meet the standard and do not contribute to a nearby violation; that regulatory judgment must be understood alongside the evidence available.
EPA’s letter says its preliminary review found no monitors with design values violating the 2024 annual standard. A design value is the calculated pollution level used to assess compliance. However, the letter’s enclosure marks the relevant monitoring fields “N/A” and does not present numerical monitoring results for the territory. An absence of identified violating monitors is therefore not the same as a complete monitoring record demonstrating clean air across the islands.
PM2.5 is the technical name for extremely small particles and liquid droplets suspended in the air. The number refers to their size: generally 2.5 micrometers across or smaller, roughly one-thirtieth the width of a human hair. These particles can include soot and other microscopic material that people breathe in, even when individual particles are too small to see.
Fuel burning is an important source. Power plants, diesel generators, vehicle engines, ships, industrial operations and refineries can release fine particles directly or emit gases that help form them. Fires and burning wood or vegetation also produce fine-particle pollution. Fine dust from disturbed soil, unpaved roads and construction can contribute, although larger dust particles belong to a different size category.
Other fine particles form after gases enter the air. Sulfur dioxide and nitrogen oxides from combustion and industrial sources can undergo chemical reactions that create particles downwind. These are general explanations of how PM2.5 is produced; the designation documents do not establish how much any particular Virgin Islands facility or activity contributes to residents’ exposure.
The health concern is that these particles can travel deep into the lungs, and some can enter the bloodstream. EPA links particle-pollution exposure to aggravated asthma, reduced lung function, heart attacks and premature death in people with heart or lung disease. Children, older adults and people with existing heart or lung conditions are among those more vulnerable to its effects.
EPA tightened the primary annual PM2.5 standard in 2024 from 12 to 9 micrograms per cubic meter of air. This measures the mass of fine particles in a given volume of air. Compliance is assessed using annual average concentrations averaged over three years, so the standard addresses longer-term exposure. The proposed designation is not a real-time air-quality reading or a determination that every location is safe at every moment.
The classification matters because a nonattainment designation triggers additional planning requirements to bring an area into compliance. An attainment/unclassifiable designation would not trigger those nonattainment requirements for this standard, but applicable emissions limits, permits and other Clean Air Act obligations would still apply. The designation itself would not authorize a refinery restart or replace a facility-specific permitting decision.
Martucci’s letter asks the territory to submit any additional information by November 1, 2026, to help EPA consider it before making a final decision. That date is separate from the public-comment process. EPA’s national notice identifies docket EPA-HQ-OAR-2024-0078 for submissions and provides for a public-comment period ending 30 days after publication in the Federal Register.
The version posted October 2 is a prepublication notice and does not yet supply the calendar date for the public-comment deadline. EPA is proceeding under a July 17, 2026 federal court order requiring final designations by February 6, 2027, while appealing that order. The agency says it intends to complete the process absent relevant judicial action, leaving the territory’s final designation subject to the review of additional information and the ongoing litigation.
