This report presents a list of chemicals emitted from California refineries, and then prioritizes the chemicals according to their emissions levels and toxicity. The report covers emissions that occur routinely in daily operations, as well as accidental and other non-routine emissions. This report does not attempt to actually measure exposure or risk in communities, but is instead a compendium of information, including health information, that may be useful for considering which chemicals to monitor near facilities, emergency response, and other efforts.
The Office of Environmental Health Hazard Assessment (OEHHA) has collaborated with the California Air Resources Board (CARB) and the Interagency Refinery Task Force to develop information on chemicals emitted from refineries and their health effects. This information can support CARB and other groups in developing plans for air monitoring in the vicinity of refineries in California. In the event of a refinery emergency, knowledge of health guidance values and emissions of chemicals can also help emergency responders characterize potential health effects that may occur following a chemical release.
In August 2012, there was a serious fire at the Chevron Refinery in Richmond, CA. During that event, an estimated 15,000 people from the nearby community sought care at local emergency departments and clinics. Follow-up investigations of the incident revealed a number of refinery safety issues. In July 2013, CARB released a report entitled “Air Monitoring for Accidental Refinery Releases: Assessment of Capabilities and Potential Improvements Project Plan.” This report laid out a stepwise plan to improve California’s refinery air monitoring and emergency response system.
In February 2014, Governor Brown issued a report titled “Improving Public and Worker Safety at Oil Refineries,”  which echoed the importance of monitoring air quality near refineries and resulted in the establishment of the Interagency Refinery Task Force coordinated by the California Environmental Protection Agency (CalEPA). In public meetings following the release of the governor’s report, community members asked if a complete list of chemicals that could be released from refineries existed, and if those chemicals had been prioritized for monitoring to ensure that monitoring systems would be tailored—insofar as feasible—to measure the most important chemicals.
As a result of these questions from the public, OEHHA compiled the information in this report. The report presents as comprehensive a list of chemicals as possible using existing data sources, and then prioritizes the chemicals according to their emissions and toxicity. This report does not attempt to estimate exposure or risk in communities.
OEHHA released a draft of this report in September 2017, while CARB concurrently released a draft report titled Refinery Emergency Air Monitoring Assessment Report. Objective 2: Evaluation of Air Monitoring Capabilities, Gaps and Potential Enhancements. OEHHA, CARB, and CalEPA participated in a series of workshops throughout California in 2018 to receive feedback on the reports. During the workshops, OEHHA did not receive any comments on its report that necessitated any changes or additions. The final OEHHA report is now being released. This report offers a useful compendium of information to assist local air districts and communities as they make decisions about air monitoring, emergency response, and other efforts related to refinery chemicals and public health.
 Governor’s Interagency Working Group on Refinery Safety February 2014 “Improving Public and Worker Safety at Oil Refineries”
OEHHA used publicly available information to compile the list of chemicals and their emissions. The California Air Resources Board’s (CARB) California Emissions Inventory Development and Reporting System (CEIDARS) Facility Search Tool was the information source for routine emissions from all refineries in California for the years 2009-2012. A second query in CEIDARs for 2014 data produced the toxicity-weighted emissions data.
We also used data on routine and non-routine emissions from California refineries reported to the U.S. Environmental Protection Agency (US EPA) as part of an Information Collection Request related to their Petroleum Refinery Sector Risk and Technology Review and New Source Performance Standards in 2011.
Additional sources included literature searches, internet databases, publicly available data, government reports, peer-reviewed journal articles, and incident databases.
The report identifies 188 chemicals emitted from California refineries, although there are large variations in the frequency, amounts and toxicity of the emitted chemicals. There is generally good information for understanding the toxicity of the identified emitted chemicals:
All of the chemicals with routine emissions greater than 10,000 pounds per year statewide (14 chemicals) have an OEHHA Reference Exposure Level (REL), which is a level of exposure that does not cause noncancer health effects. OEHHA did not attempt to determine whether or how often these exposure levels may have been exceeded in areas near refineries.
107 chemicals have at least one health guidance value from OEHHA or US EPA and 94 chemicals have at least one emergency exposure value to evaluate the harm of large unanticipated releases. Overall, of the listed chemicals have none of the types of health guidance values described here; however, the absence of health guidance values does not necessarily mean that the chemicals are not hazardous. In addition, these chemicals are generally released in much lower quantities than those with guidance values.
The ten most frequently reported routine toxic air contaminant emissions from California refineries from 2009-2012 (starting with the highest) were:
OEHHA also used additional data for routine and non-routine emissions of all pollutants (not just TACs) that California refineries reported to the US EPA for the year 2010 only. Using these data, OEHHA determined the most frequently emitted chemicals (starting with the highest) were:
Of the 188 chemicals identified as emitted from California refineries, the chemicals listed below are the top candidates for air monitoring, based on their toxicity, average levels of emissions from refineries statewide, and involvement in multiple refinery processes and incidences. OEHHA also derived a “toxicity-weighted” emissions score for each chemical for which emissions data were available for all refineries across California. OEHHA calculated the toxicity-weighted emissions scores using emissions data (pounds emitted per year) obtained from the Air Toxics ‘Hot Spots’ Emissions Inventory database (CEIDARS) for 2014, and a toxicity weight derived from US EPA’s Inhalation Toxicity Scores for individual chemicals. The candidate chemicals that had high calculated toxicity-weighted emissions are noted in the candidate list below with an asterisk (in alphabetical order).
These candidates for air monitoring were not further ranked or prioritized.
An important consideration for air monitoring at individual refineries is that the candidate chemicals will differ based on location as well as year. Some top-candidate chemicals are only released in small amounts from individual refineries.
Finally, the release of these chemicals from refineries does not necessarily mean that local communities face substantial exposures or significant health risks. However, it does increase their likelihood of exposure. Air monitoring of these chemicals may inform decisions that could reduce exposure.