Air Toxics

The Air Toxics “Hot Spots” Act requires CARB to compile and maintain a list of substances posing cancer or chronic or acute health impacts when present in the air. Over 600 substances have been listed under the act.

Ventura County facilities are subject to the act if they manufacture, formulate, use or release a listed substance and either emit 10 tons or more per year of criteria pollutants (total organic gases, particulate matter, nitrogen oxides or sulfur oxides) or less than 10 tons per year of criteria pollutants.

Facilities submit inventory plan and report

The Air Toxics “Hot Spots” Act requires subject facilities to prepare air toxics emission inventory plans and, subsequently emission inventory reports. The Emission Inventory Criteria and Guidelines Report, which was first approved by CARB in 1989, provides specifications for acceptable emission inventory plans, reports and updates. Portions of the guidelines were amended by CARB several times since then. The current version of the guidelines became effective in 2007.

Facility operators must submit to the district a proposed emission inventory plan indicating how emissions will be measured or calculated. The district must approve, modify or return the inventory plan to the operator for revisions within 120 days. Once the district approves a plan, the facility operator must implement the plan and submit the emission inventory report within 180 days. For certain classes of facilities, the district must prepare industrywide inventories. In this case, individual facility reports are not required. The district determines which facilities will be covered by industrywide inventories based on conditions such as economic hardship and small business status.

Facilities subject to the program must update their emission inventories every four years. The update requirements were streamlined in 1993 and are now based on each facility’s prioritization category. The new update requirements substantially reduce reporting requirements for all but the significant risk facilities.

District sets priority level

After reviewing emission inventory data, the district ranks facilities for purposes of risk assessment into high, intermediate and low priority categories. Facilities are reprioritized if their inventory update shows any significant changes.

In establishing priorities, the district considers the potency, toxicity and quantity of hazardous materials released from the facility, the proximity of the facility to potential receptors and any other factors that the district determines indicate that a facility may pose a significant risk.

The California Air Pollution Control Officers Association (CAPCOA) has developed Air Toxics “Hot Spots” Program Facility Prioritization Guidelines to provide districts with suggested procedures for use in prioritizing facilities. These guidelines were updated in 2016. The Ventura County Air Pollution Control Board adopted Prioritization Procedures based on the CAPCOA guidelines. The Prioritization Procedures were amended to incorporate the updated CAPCOA guidelines in 2023.

High-priority facilities assess health risk

Within 150 days of the designation of priorities, high priority facilities must prepare and submit a health risk assessment to the district. A risk assessment, as defined under the Air Toxics “Hot Spots” Act, includes a comprehensive analysis of the dispersion of hazardous substances into the environment, the potential for human exposure and a quantitative assessment of both individual and population-wide health risk associated with those levels of exposure. The district may grant a 30-day extension for submittal of the risk assessment. The risk assessments are reviewed by the district and OEHHA.

OEHHA has developed the 2015 Air Toxics Hot Spots Program Risk Assessment Guidelines for preparing the health risk assessments required under the Air Toxics “Hot Spots” Act. These guidelines replaced a version released in 2003. The update to the Risk Assessment Guidelines was triggered by SB 25, Children’s Environmental Health Protection, which required that the increased sensitivity of infants and children to toxics be specifically addressed. CAPCOA and CARB adopted the Risk Management Guidance for Stationary Sources of Air Toxics, which should be used to prepare “Hot Spots” risk assessments. Use of the OEHHA guidelines is required by law. CARB has developed the Hotspots Analysis and Reporting Program (HARP) software, which can be used to prepare “Hot Spots” risk assessments. Meteorological data for Point Mugu and Camarillo and Oxnard airports to be used for risk assessment dispersion modeling is available on the CARB website. Additional meteorological data sets also are available from district-operated air monitoring stations in El Rio, Ojai, Piru, Simi Valley and Thousand Oaks.

District notifies public

The CAPCOA Toxics Committee has also developed Public Notification Guidelines to assist districts. The Ventura County Air Pollution Control Board has adopted public notification procedures based on the CAPCOA Guidelines.

Facilities found to have a significant risk must conduct an airborne toxics risk reduction audit and develop a plan to implement reduction measures. The audit and plan must be submitted to the district within six months of the determination. They must describe the methods the facility will use to reduce risk below the level of significance within five years. The district may shorten or lengthen the time period (up to five additional years) under certain conditions.