Shelby County's top five pollution sources have a name now: Nucor Steel, Valero, Draslovka, TVA's Allen Combined Cycle Plant and Mitsubishi Chemical of America. Three of those facilities sit in ZIP code 38109, while the other two are located in 38127, according to county data. The disclosure comes as the agency responsible for policing those emissions says it's running short on the money to do the job.
The Shelby County Health Department identified the five facilities as the county's leading pollutant sources, according to the Memphis Flyer. The same five companies were confirmed by WREG, which reported that the top sources are concentrated in the 38109 and 38127 ZIP codes. Those two ZIP codes cover industrial corridors in southwest Memphis that have long drawn scrutiny over air quality.
The geographic split is notable: three of the five leading sources cluster in 38109, while the remaining two sit in 38127, per the Memphis Flyer's reporting. The county has not detailed which specific facilities fall into which ZIP code beyond that breakdown.
Where xAI Fits on the List
Amid public attention on data centers and their power demands, Shelby County Health Department officials have said SpaceXAI ranks far below the five leading industrial sources. The department told county commissioners in September that xAI placed 28th on the county's pollution list, the station reported, with its facilities located in the Boxtown and Whitehaven areas. That ranking puts xAI well outside the top tier dominated by Nucor Steel, Valero and the other major emitters named by the Health Department.
The Health Department's Air Pollution Control Branch is the agency responsible for tracking all of it. Per the Shelby County Health Department, the branch administers construction and operating permits, conducts facility inspections and air-pollution testing, shares air-pollution information with the public, and enforces air regulations. The department classifies sources into three categories: Title V major sources, minor sources, and synthetic minor sources — the last being facilities that voluntarily accept permit limits to keep their emissions below the threshold that would otherwise classify them as major polluters.
A Shrinking Budget for a Growing Watchlist
The timing of the disclosure lines up with a funding squeeze inside the department itself. The Health Department operates a $900,000 Air Pollution Control Program and said it is currently $90,000 short of what it needs to run it, according to the station's report. Officials have tied that shortfall directly to the same facilities now being named as top emitters: as large industrial sites emit less pollution, the department collects less in permitting revenue, the Memphis Flyer reported.
The numbers bear that out. The department projected $900,000 in Title V program revenue for 2025 but ultimately received $822,783, per the Flyer's reporting. For 2026, the department expected $805,000 and ended up receiving slightly more, $810,000 — a modest rebound, but still well below where officials initially hoped to land just a year earlier.
What Counts as a Major Polluter
The classification system matters because it determines how closely a facility gets watched. A facility can qualify as a Title V major source based on the potential to emit 10 tons per year of any hazardous air pollutant, 25 tons per year of combined hazardous air pollutants, or 100 tons per year of any regulated air pollutant, according to the Shelby County Health Department. Anyone planning to build a new regulated air-contaminant source must submit a permit application before construction begins, the department notes.
Separately, federal regulators have pursued enforcement tied to one of the five companies named locally. A settlement involving petroleum refiner Valero is expected to reduce harmful air emissions by more than 20,000 tons per year across 14 refineries in six states, according to the U.S. Environmental Protection Agency. That figure reflects the settlement's multi-state scope rather than Shelby County alone.
For residents in 38109 and 38127, the county's new accounting offers a clearer picture of who is emitting what — even as the agency charged with enforcement says it's stretched thin trying to keep up.
