Baykeeper Update

Air Emissions from Lehigh Cement Amplify Mercury Contamination of San Francisco Bay

Lehigh Southwest Cement Company’s Permanente Plant has spewed toxic mercury into the air since 1939. The Plant, which is located in Cupertino, emits approximately 435 pounds of mercury from its smokestacks each year, making it the largest source of mercury pollution in the Bay Area.

The Lehigh Plant (formerly Hanson) mainly produces Portland cement, a fine gray powder that is used as a binding agent in concrete. Portland cement is made by blending limestone with other raw materials, heating the mixture to produce “clinker” pellets, and then grinding the clinker with gypsum to form the cement. In addition to the cement plant, the company’s facility also contains an on-site quarry for mining the Plant’s raw materials that is over a hundred years old. Both the fuel and the raw materials used by the Plant contain high levels of mercury.

Aerial Deposition of Mercury

Mercury is an extremely hazardous pollutant that accumulates in aquatic food chains, endangering sensitive species and human health. Once mercury is in the environment, it is converted into an organic compound called methylmercury – a persistent neurotoxin that builds up, or bioaccumulates, in ecosystems. Studies show that methylmercury exposure can trigger neurological, reproductive, developmental, immunological, and cardiovascular problems for wildlife and people that eat contaminated fish or shellfish.

Mercury enters the San Francisco Bay through a process known as aerial, or atmospheric, deposition. Aerial deposition occurs when airborne pollutants fall directly onto the surface of a waterbody or reach a waterbody indirectly by falling onto land and subsequently washing off during storm events. Aerial deposition is increasingly recognized as a significant cause of water quality impairment, ocean acidification, and aquatic life toxicity.

Mercury TMDL for the San Francisco Bay

In 2006, the Regional Water Board adopted a Total Maximum Daily Load (TMDL) to reduce mercury contamination in the San Francisco Bay, which is less than 10 miles from the Lehigh Cement Plant. A TMDL calculates the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards. Under the Clean Water Act, a state must develop a TMDL whenever a waterbody is deemed “impaired” from discharges of a particular pollutant.

Despite the U.S. Environmental Protection Agency’s (EPA) guidance for producing TMDLs that address aerial deposition of pollutants, the San Francisco Bay Mercury TMDL mainly focuses on reducing pollution from wastewater and stormwater. The TMDL acknowledges that aerial deposition is a source of mercury contamination in the Bay, but does not require any pollution reductions from this source. As a result, the continued operation and expansion of the Lehigh Cement Plant will release even more toxic mercury into the San Francisco Bay.

 New EPA Regulations Aim to Reduce Mercury Emissions from Cement Plants

To address the nation-wide problem of harmful air emissions from facilities that manufacture Portland cement, the EPA recently amended the National Emission Standards for Hazardous Air Pollutants (NESHAP) under the Clean Air Act (CAA). Under the revised standards, all new and existing Portland cement facilities must dramatically reduce mercury, particulate matter, total hydrocarbons, and hydrochloric acid emissions by September 9, 2013 (see 40 CFR part 63, subpart LLL). In addition, the NESHAP amendments require cement manufacturing facilities to upgrade their emission monitoring equipment to ensure compliance with the new standards.

According to the EPA, the new standards will reduce mercury emissions from the Portland cement industry by about 16,000 pounds, a 92 percent reduction from the projected emission levels for 2013. The EPA also projects that the standards will result in 7 to 19 dollars of public health benefits for every dollar spend on implementing the amendments. The Portland cement industry is currently the third-largest source of mercury emissions in the United States.

The Lehigh Cement Plant plans to install several new emission control technologies to comply with the NESHAP amendments. However, the NESHAP amendments are far more stringent than the previous standards for the Portland cement industry, presenting the Plant with the difficult task of quickly and dramatically reducing its hazardous air emissions over the next two and a half years.

Proposed Renewal of Lehigh Cement’s CAA Title V Permit

In April 2008, the Lehigh Cement Plant submitted an application to renew its permit for air emissions under Title V of the CAA. Due to the expected release of the EPA’s new emission standards for the Portland cement industry, the Bay Area Air Quality Management District did not issue a draft permit for the facility until January 2011. See Baykeeper’s comments on the proposed renewal of Lehigh’s Title V permit, as attached below.

Baykeeper is working to ensure that the NESHAP amendments are effectively implemented and enforced at the Lehigh Cement Plant.