1993-09-00 Air Toxics Update #9

This page last reviewed July 30, 2008


Air Toxics Update #9




This update is the ninth in a series of publications summarizing recent activities in California's air toxics program. It covers legislative actions affecting the program, recent Board decisions on toxic air contaminant (TAC) identification and control, an update on the Air Toxics "Hot Spots" Assessment program, and information on proposed future activities addressing air toxics management in California. Previous updates are available in the Air Resources Board (ARB) Public Information Office.


California's air toxics program continued to evolve during the past year. Activities ranged from the passage of new air toxics legislation, to the development of guidelines for carrying out air toxic programs.          

With the signing into law of AB 2728 (Tanner) and SB 1731 (Calderon), substantial changes to both the Toxic Air Contaminant (TAC) program and the Air Toxics "Hot Spots" program have been enacted. AB 2728 requires specific actions to be taken by the ARB to bring about greater uniformity between the California and federal air toxics programs. SB 1731 builds on the existing AB 2588 program, adding a risk management element.

Board actions in the early months of 1993 included the identification of 189 federal hazardous air pollutants (HAPs) as TACs, as required by AB 2728, as well as the adoption of an airborne toxic control measure (ATCM) for non-ferrous metal melting facilities. Additionally, the Board approved the Risk Management Guidelines to aid air districts in permitting new and modified facilities which emit air toxics. The Air Toxics "Hot Spots" program is entering its third phase of emissions reporting. The emission inventory process has been streamlined to reduce update requirements for all but the most significant risk facilities. The Cal/EPA's Office of Environmental Health Hazard Assessment (OEHHA) is now required to prepare new risk assessment guidelines, and the California Air Pollution Control Officers Association has issued Public Notification Guidelines.


Two pieces of California legislation passed in 1992 and signed into law by Governor Pete Wilson will significantly strengthen California's air toxics program.

AB 2728 (Tanner)

The Tanner bill integrates the federal air toxics program and California's TAC Identification and Control program The bill clarifies ARB's authority to implement the federal air toxics program and take whatever action is needed to seek delegation. Tanner's bill amends the current TAC program in several areas.

The bill specifies the ARB must, by regulation, identify as TACs, the 189 substances the federal government has listed as HAPs. The prioritization of compounds must now consider specified data bases (e.g., Superfund Amendments and Reauthorization Act list and the "Hot Spots" list), and estimated actual exposures to the extent data are available.

Promulgated federal emission standards will become state ATCMs under the new law. In those cases where the state has specified an emission standard more stringent than the federal standard, the state standard shall prevail. The ARB may also revise the federal standard to meet the purposes of the TAC identification and control program. For sources where there is not a federal emissions standard, ATCMs may be adopted following the current process.

The bill requires air toxics control reports to address additional items, especially those related to risk. For example, the reports must address the risk associated with the various levels of emissions and human exposure and how the control measure will reduce risk. In addition, the report must address how the measure is compatible with other technological improvements implemented by affected sources.

When a control measure requires the use of a specified method to reduce emissions of a TAC, a source may submit an alternative, enforceable method to the district that will achieve an equal or greater amount of emissions reduction.

SB 1731 (Calderon)

The Calderon bill amends the AB 2588 Air Toxics "Hot Spots" Information and Assessment program by adding two new major elements. First, the Office of Environmental Health Hazard Assessment (OEHHA) must prepare and adopt risk assessment guidelines. Secondly, significant risk facilities must prepare and implement risk reduction audits and plans (RRAPs). The ARB is required to provide assistance to smaller businesses for developing and applying risk reduction techniques. As part of that assistance, the ARB will develop a self-conducted checklist for industries comprised mainly of small businesses.

The new risk assessment guidelines will allow facilities to include "supplemental information" such as alternative risk exposure parameters with likelihood distributions, micro-environmental characteristics, population distributions, and descriptions of incremental reductions of risk when exposure is reduced. The guidelines will offer the districts guidance on how to use the supplemental information. The OEHHA risk assessment guidelines will be developed with full public participation and will then be evaluated by the Scientific Review Panel (SRP) on Toxic Air Contaminants.

A RRAP must be submitted by a facility to the district within six months of determination by the district that the facility poses a significant risk. The implementation of the RRAP must reduce emissions below the significant risk level within five years. However, the district may shorten that timeframe or lengthen it up to a maximum of 10 years.

The district's review of completeness shall include a substantive analysis of the emissions reduction measures. The district has three months to conduct the review. Facilities must resubmit a revised RRAP within 90 days. Fees may be assessed by the district, ARB, or OEHHA in an amount sufficient to cover the costs of carrying out the program.


Adoption of an Airborne Toxic Control Measure for Emissions of Toxic Metals from Non-Ferrous Metal Melting

In January 1993, the Board approved an ATCM requiring facilities to reduce their emissions of cadmium, inorganic arsenic, and nickel. Facilities covered include foundries, smelters, and galvanizers. This ATCM will reduce cadmium, arsenic, and nickel emissions from non-ferrous foundries, smelters, and galvanizers by 70 percent, 11 percent, and 25 percent statewide respectively, through the application of best available control technology. Also, lead emissions from these facilities will be cut by 45 percent statewide because lead is emitted from many of the facilities subject to this ATCM. The same pollution control devices also reduce lead.

The control measure requires specified emission reductions or control efficiencies which must be achieved, but does not dictate the type of control equipment to be used. Source testing is required to demonstrate compliance with these requirements. Facilities that melt certain metals very low in cadmium and arsenic, and facilities that melt no more than specified quantities of specific types of metals, are exempt from the emission control and fugitive emissions reduction measures and source testing requirements.

Board Adoption of a Regulation Designating Federal Hazardous Air Pollutants as Toxic Air Contaminants    

At its April 1993 Board meeting, in accordance with AB 2728, the Board identified the 189 federal HAPS as TACs. The 189 HAPS will be evaluated and prioritized by the ARB for development of health assessment values by the OEHHA. The health assessment values will be submitted to the SRP for approval.

Risk Management Guidelines

At its July 1993 Board meeting, the Board approved Risk Management Guidelines for new and modified stationary sources of toxic air pollutants. The guidelines will promote statewide uniformity among districts in designing permitting programs to evaluate cancer and noncancer risks from toxic air pollutants.

The guidelines suggest that districts use a combination of specific risk levels and ranges for evaluating approval of new and modified sources of toxic air pollutants. As estimated exposures and risks associated with a new project increase, actions ranging from requiring best available control technology to disapproving a project are recommended.

In addition to assessing cancer and noncancer risks for approval of a project, other factors such as the benefits of the project, the uncertainty in the risk assessment process, and the impact of the project on sensitive receptors can be considered. A discussion of these other factors would be provided in a Specific Findings Report prepared by the applicant. The Air Pollution Control Officer reviews this report and prepares findings supporting a decision to approve or deny the project.

The guidelines provide risk managers with flexibility by recommending the use of risk levels and ranges for making permitting decisions. The guidelines are designed to promote uniformity among the various risk-based permitting programs used by the districts and will aid in the development of consistent regulatory requirements statewide.


Streamlining the Emission Inventory Criteria and Guidelines Regulation

Currently, most larger facilities in California have completed their first cycle of air toxic inventory updates. The "Hot Spots" Act requires inventories to be updated every two years. Based on an evaluation of the emission inventory process, amendments to the Guidelines Regulation were adopted by the Board at its June 1993 meeting to streamline the inventory update requirements. Biennial update requirements are now based on each facility's prioritization category. Inventory update efforts focus on facilities with the greatest potential public health impact and have been greatly reduced for all other affected facilities. Facilities identified as significant risk will still be required to submit a complete inventory update. Most other facilities will now only be required to submit a new two- page biennial summary form to satisfy their update requirements. The amendments will greatly reduce cost and burdens to affected facilities.

In addition to changing the biennial update requirements, the following modifications were also made to the regulation: 1) provisions were added to allow a facility that no longer meets the definition of applicability (as specified in the regulation) to be removed from the program if it is not a significant risk to public health; 2) instructions were added to allow source test results in which all values are below the test methods analytical limit of detection to be reported as non-detect; 3) certain source test requirements were eliminated for publicly owned treatment works and emergency diesel equipment for which testing was determined to be infeasible or impractical; 4) minor revisions were made to the core reporting forms, and 5) reporting form instructions were reorganized and clarified.

The ARB maintains the emissions data collected under this program in a comprehensive statewide database. The emissions data from the larger facilities in California are now available to the public.

Public Notification Guidelines

The California Air Pollution Control Officers Association (CAPCOA) Public Notification Guidelines provide districts with a tool which can be used to develop notification procedures under the Air Toxics "Hot Spots" Program. The intention is to provide districts with clear procedures for facilities which are required to notify the public under the Air Toxics "Hot Spots" program. For instance, the guidelines include examples of notification materials and suggestions for presenting such information. The guidelines also include recommendations for the role of the facility and district in notification.


In support of the Department of Pesticide Regulation (DPR) toxic air contaminant program, ARB measures concentrations of pesticides present in the outdoor air, and around fields during and immediately following application. Since the program began, ARB has conducted air monitoring for 20 pesticides at the request of DPR and four pesticides at the request of other agencies. Monitoring is conducted when and where a pesticide is most heavily used.

ARB continues to work with DPR, OEHHA, and the pesticide manufacturer regarding possible limited reintroduction of the soil fumigant Telone. The manufacturer is modifying application procedures to reduce potentially harmful levels of emissions. The use of Telone, for the control of nematodes, was suspended by DPR in 1990 based on results of air monitoring conducted by the ARB. ARB is working with DPR to develop permit conditions for the use of methyl bromide, and is participating in the review of alternatives that may be used when methyl bromide production is phased out after the year 2000 due to its potential to deplete stratospheric ozone.


The ARB staff provides technical assistance to the Department of Toxic Substances Control (DTSC) and local air districts on assessing public exposure to emissions from hazardous waste facilities and waste sites undergoing cleanup activities. The ARB recommends procedures for estimating emissions and approves air monitoring plans. Currently, ARB is assisting with development of a guidance document to aid DTSC staff in evaluating air impacts at hazardous waste site clean up projects.


Concern that solid and hazardous waste landfills may be sources of toxic emissions to the outdoor air led to a requirement that all operating and some closed landfills must carry out testing to identify potential public health problems. ARB has compiled a database from test reports and data summaries from over 445 landfills which were required to conduct testing. Test results indicating underground methane gas migration away from landfills have been shared with the California Integrated Waste Management Board which has the authority to regulate this potential hazard. Landfills where gases were detected outside the landfill are being further investigated with the air districts to see if they pose a threat to public health.


At its May 1993 meeting, the SRP evaluated acetaldehyde as a TAC. Benzo[a]pyrene should be considered by the Panel sometime in 1994. Inorganic lead and diesel exhaust are compounds expected to be considered for identification by the Board during the next 12 months. During this same period, a control measure for perchloroethylene is scheduled to be considered by the Board. For further information about ARB's TAC program, please contact:

Air Resources Board
Stationary Source Division
2020 L Street
Sacramento, CA 95814
(916) 445-0650


Air Toxics Updates