BAKERSFIELD — The public has until 5 p.m. on Friday, Oct. 30, to comment on a proposed five-year renewal of the federal air quality permit for U.S. Borax’s mine and refinery in Boron, according to the Eastern Kern Air Pollution Control District.
Comments may be submitted in writing or emailed to ekapcd@kerncounty.com. The draft permit and the district’s technical support document can be downloaded from the district’s website. Copies also may be reviewed at the district’s administrative office, 2700 M St., Suite 302, Bakersfield. The office phone number is 661-862-5250.
The draft is a federal Part 70 permit, issued under district Rule 201.1, which governs sources subject to Title V of the federal Clean Air Act Amendments of 1990. The district issued U.S. Borax’s first Title V permit in 2001. According to the district, no significant modifications have been made to the permit since its last issuance. The new permit will be valid for five years once the district issues it and the U.S. Environmental Protection Agency approves it.
U.S. Borax, owned by Rio Tinto, operates at 14486 Borax Road, Boron. The district’s technical support document describes the operation as California’s largest open-pit mine and says the company supplies nearly half the world’s demand for refined borates.
District documents show that the current permit was renewed April 28, 2020, and expired April 28, 2025. U.S. Borax submitted its renewal application Oct. 24, 2024, and the district deemed it complete Nov. 22, 2024. The district then set the renewal aside while it finished issuing authority-to-construct permits and inspecting new emissions units, so that all of them could be included in the renewal. The company has operated under what the district calls an application shield in the meantime.
The district noted it sent the proposed draft to U.S. Borax for a 45-day review on May 7, 2026. The EPA’s 45-day review began Oct. 1 and ends Nov. 14. If the district receives no comments, the permit will be finalized and a final draft submitted to the EPA, according to the technical document.
Since the 2020 renewal, 20 equipment units have been added and 18 taken out of service with their permits canceled, the technical document says. Others were modified. The district considers all of the changes minor facility modifications that did not require public notice. New units include diesel-powered emergency and prime water pumps, street and floor sweepers, industrial vacuum units, a portable stacker, a portable dry bulk loading system and an anhydrous boric acid loadout.
The document lists plant-wide emissions for 2024 of 708.07 tons of PM10, 720.09 tons of nitrogen oxides, 491.7 tons of carbon monoxide, 42.06 tons of volatile organic compounds and 10.52 tons of sulfur oxides. It also lists greenhouse gas emissions of 382,829.58 tons of carbon dioxide equivalent.
The district’s compliance summary for 2020 through 2025 lists three notices of violation. One cited Rules 209.1 and 210.1 for Dec. 18-19, 2020, and was settled March 1, 2021. Two cited Rule 201, on March 27 and May 2, 2024, and were settled April 4 and May 20, 2024. The district also lists a variance for the cogeneration plant, with a hearing Oct. 16, 2025, and completion Jan. 24, 2026.
Source: kernair.org