What is DPR’s Toxic Air Contaminant Program?

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With the enactment of California’s Toxic Air Contaminant Act (Assembly Bill 1807, Tanner, Chapter 1047, Statutes of 1983; amended by Tanner, Chapter 1380, Statutes of 1984), the Legislature created the statutory framework for the evaluation and control of chemicals (including pesticides) as toxic air contaminants (TACs). (Food & Agricultural Code sections 14021-14027). The statute defines TACs as air pollutants that may cause or contribute to increases in serious illness or death, or that may pose a present or potential hazard to human health. Chemicals the federal government classifies as hazardous air pollutants (HAPs) are administratively listed and not subject to the evaluation provisions of the TAC statute. However, they are subject to reevaluation and possible restrictions under other statutory mandates. The Air Resources Board (ARB) is the lead agency for nonpesticidal uses of chemicals in air. DPR is responsible for evaluating pesticidal uses of chemicals as TACs.

The law focuses on identifying, evaluating and controlling pollutants in ambient community air. In carrying out the law, DPR must:

  • Evaluate the physical properties, environmental fate and human health effects of the candidate pesticide.
  • Find out the levels of the pesticide in air.
  • Estimate human exposure and the potential human health risk from those exposures.

The law requires DPR to list in regulation both those pesticides previously identified under federal laws as HAPs (HAP-TACs) and those identified by DPR through the evaluation process of the TAC statute. DPR must decide the appropriate degree of control measures for any HAP-TAC that has gone through a peer-reviewed risk assessment process and for a pesticide that has been evaluated and listed through the evaluation process required by the statute.

DPR’s TAC Program consists of two phases: risk assessment (evaluation and identification) and risk management (control). The first phase involves an extensive evaluation of the candidate pesticide to assess the potential adverse health effects and to estimate levels of exposure associated with its use. As part of the estimate of exposure levels, DPR requests ARB to conduct monitoring studies to measure the air concentrations of pesticides. For each candidate pesticide, ARB collects samples near an application site and in ambient air of nearby communities. Because most large-scale pesticide applications are seasonal and occur in agricultural areas, ARB conducts monitoring in areas of high use, and at times when use is at its peak. This worst-case information can help determine the ambient exposures of people living in all areas where the pesticide is used.

Continuing the evaluation for each pesticide, the law requires DPR to prepare a report that includes:

  • An assessment of exposure of the public to ambient concentrations of the pesticide.
  • A risk assessment which includes data on health effects including potency, mode of action and other biological factors.
  • A review of the environmental fate and use of the pesticide.
  • The results of monitoring studies conducted in California to measure the levels of the candidate pesticide in ambient air.

The draft report is peer-reviewed by CalEPA’s Office of Environmental Health Hazard Assessment (OEHHA) and the ARB and is made available for public review. Based on the results of these reviews, DPR scientists revise the draft report as appropriate, which includes OEHHA’s separate findings. The draft undergoes a rigorous peer review for scientific soundness by the TAC Scientific Review Panel (SRP), a panel of experts representing a range of scientific disciplines. Based on this comprehensive evaluation, DPR receives a recommendation from the SRP whether the pesticide meets the criteria for listing as a TAC. If the pesticide meets the criteria, DPR adopts a regulation listing it as a TAC.

Once a candidate pesticide is listed as a TAC or a risk assessment is completed for a HAP-TAC, it enters the mitigation phase. Consulting with OEHHA, ARB and local air pollution control districts, DPR must make a written determination on the need for and suitable degree of controls. If reductions in exposure are needed, DPR must develop control measures to reduce emissions to levels that adequately protect public health, in consultation with agricultural commissioners and air pollution control districts. Additional agencies are also consulted as required by other legal mandates or policy. DPR must use the best practicable control techniques available, which may include:

  • Requesting that the registrant work with U.S. EPA to change use instructions on the product label.
  • Applicator training.
  • Limits on application methods, crops, or locations.
  • Reclassifying the pesticide as a restricted material, meaning that a site-specific permit would be required and added controls imposed, based on local conditions.
  • Banning the use by canceling a product’s registration.

DPR must adopt control measures within two years of determining that reductions in exposure are needed, or submit a report to the Legislature describing the reasons why the two-year deadline cannot be met. DPR and other organizations may conduct monitoring or data analysis to determine the necessity or effectiveness of control measures.

DPR’s TAC program is one of several options DPR can use to control airborne pesticide residues. DPR has broad authority over the registration, sale and use of pesticides in California to protect public health and the environment. This authority is derived from several laws that cover all aspects of pesticide use in all media -- air, ground and surface water, food, and in agricultural, industrial, institutional, occupational and home-and-garden settings. This regulatory authority allows DPR wide latitude to regulate application rates, ensure pesticide efficacy, designate pesticides as restricted materials, develop criteria to prevent unacceptable pesticide residues in food and water, license applicators and dealers, and adopt rules to protect workers and the public from overexposure. This full exercise of DPR’s authority extends to the suspension of a pesticide’s registration, ending all use immediately if evidence supports that action.