In 1987, the California legislature adopted the Air Toxics “Hot Spots” Information and Assessment Act (Assembly Bill 2588, or AB 2588). The goals of the Act are to collect emissions data of toxic air contaminants, identify facilities having localized impacts, determine health risks, notify affected individuals, and reduce adverse health risks.
Quemetco has three types of toxic emission sources: smelting, administrative building ventilation, and fugitives (surface deposition). The smelting processes (crushing, melting, and metal recovery and refinement) are completely contained within several buildings and exhausted through a series of scrubbers, baghouses, a Wet Electrostatic Precipitator (WESP), and a regenerative thermal oxidizer (RTO). The building ventilation exhausts are controlled with particulate filters. The surface fugitives are controlled with daily washdowns and a mechanic sweeper.
As required by AB 2588, Quemetco has conducted a series of Health Risk Assessments (HRAs) and Risk Reduction Plans (RRPs) since 2000. An HRA is a technical study that evaluates how toxic emissions are released from a facility, how they disperse throughout the community, and the potential for those toxic pollutants to impact human health. If the results of the HRA exceeds action risk thresholds, the facility must prepare an RRP and implement it within two and half years of its approval. Further information on the AB 2588 program at South Coast AQMD can be found on our Air Toxics "Hot Spots" Program (AB 2588) page.
2000 Health Risk Assessment and 2006 Risk Reduction Plan
Ambient measurements of lead near Quemetco showed levels above the National Ambient Air Quality Standard (NAAQS). As a result, Quemetco was required to prepare an HRA in December 2000. The maximum individual cancer risks modeled in the HRA were 33.4 in a million. In response to comments at several public meetings, South Coast AQMD modified the original HRA based on local meteorological data and emissions representative of their current operations.
The modified HRA approved on December 16, 2005 estimated the maximum individual cancer risk at 21.8 in one million - primarily from arsenic and 1,3-butadiene emissions. While this risk was lower than that estimated in the original HRA, levels still triggered public notifications and a RRP under South Coast AQMD rules. Quemetco notified the public of the risks on January 17, 2006, and the Public Notification Meeting was held on February 1, 2006. Quemetco’s RRP was submitted on April 11, 2006 and approved on May 12, 2006. The 2006 Risk Reduction Plan included installation of air pollution controls, including a Wet Electrostatic Precipitator (WESP) to control particulates and metals, and installation of a regenerative thermal oxidizer to control organics.
As part of the approval of the RRP, Quemetco conducted tests to confirm their emissions in January 2009, and prepared and submitted another HRA to demonstrate compliance with South Coast AQMD rules. The emissions tests and subsequent HRA assumed the maximum throughput of 600 tons/day, as specified in their permit to operate. The HRA was approved on February 23, 2010. The 2010 HRA estimated a maximum individual cancer risk of 4.4 in one million, an 80 percent reduction in cancer risk, a level that did not require further action by the facility.
2014 Health Risk Assessment and 2016 Risk Reduction Plan
In October and November 2013, South Coast AQMD staff conducted additional emissions tests at Quemetco. The results of these tests showed higher arsenic, benzene, and 1,3-butadiene emissions compared to previous tests in 2009, 2010 and 2012. As a result, Quemetco was required to prepare and submit a new HRA. Quemetco submitted this HRA on May 19, 2015. After several revisions to correct monitoring data and modeling inputs, South Coast AQMD staff approved the HRA on May 17, 2016. The approved HRA showed a residential maximum individual cancer risk of 16 in one million and showed higher non-cancer risks and cancer burden, requiring additional public notification of the risks and a new RRP.
The new RRP was submitted on November 16, 2016. As part of this plan, Quemetco proposed using a continuous emissions monitor to ensure that the metals emissions and associated risks remained low. South Coast AQMD conditionally approved this plan on June 22, 2017. The conditions for approval established not-to-exceed levels for arsenic and lead that were measured using a real time emissions monitor, and intermediate notification thresholds that would trigger notifications to South Coast AQMD and require Quemetco to propose additional controls. The intermediate notification thresholds are designed for Quemetco to take action before the not-to-exceed levels reached.
The links below provide additional information:
Public Notification Meeting:
Health Risk Assessment Documents: