The Science Advisory Board on Toxic Air Pollutants (SAB) was chartered by the Secretary of the Department of Environment and Natural Resources (DENR) to make recommendations to the Environmental Management Commission (EMC) to minimize the potential health hazards resulting from exposures to toxic air pollutants. The SAB is composed of seven individuals, appointed to four-year terms, having expertise in Environmental Health, Occupational Medicine, Toxicology, Risk Assessment, Exposure Assessment, and Biostatistics. The SAB meets regularly to perform risk assessments on toxic air pollutants emitted in North Carolina. Their final recommendations are considered by DENR in drafting rules for acceptable ambient level (AAL) concentrations for toxic air pollutants.

The Division of Air Quality (DAQ) is delegated the responsibility for managing the agenda of the SAB. The priorities are determined by a flexible set of criteria that allows DENR the ability to respond to potential inadequacies in the present regulatory system identified by the NC Department of Health and Human Services and/or affected citizens of North Carolina. In general, these response-type requests take ultimate priority over the other duties of the Board. The SAB may also be directed to make recommendations for hazardous air pollutants (HAPs) which are emitted in significant quantities in North Carolina but do not have State toxic air pollutant (TAP) guidelines. A list of these chemicals is generated and prioritized by DAQ through a combined assessment of emissions levels, toxicological properties, and potential present and future human exposures. The list is then given to the SAB for risk assessment. In addition, the SAB may also be asked to conduct site-specific risk assessments, assess health risks due to exposure to chemical mixtures, consider multi-media effects on exposure and/or consider other specific topics of importance to DENR.

The SAB uses scientific risk assessment methods and standard practices to arrive at recommendations for AALs for toxic air pollutants emitted in North Carolina. The SAB generally considers pollutants on a chemical-by-chemical basis, and relies on current, relevant, peer-reviewed toxicological literature and presentations made by expert toxicologists for information. Multiple AALs for a single chemical are recommended by the SAB using a "range of risks." That is multiple AALs for the same chemical may be recommended based on different toxicological endpoints (e.g., acute exposure, chronic exposure, effect on central nervous system, effect on respiratory system). Toxics Protection Branch staff are then responsible for assigning averaging times for AALs based on the based on the toxic effect(s) noted by the SAB. Recommendations are then sent to the DAQ Planning Section for rule development. Proposed rules, incorporating the recommended AALs are presented to the Air Quality Committee (AQC), a part of the Environmental Management Commission (EMC) for consideration.

If the AQC response to the proposed rules is positive, public hearings are held on the draft rules. The hearing officers evaluate all statements and data presented at public hearings and these evaluations are presented to the AQC. If the draft rule is approved by the AQC, it is forwarded to the EMC. If the EMC affirms the draft rule, it becomes a regulation.

View a copy of the current Air Quality rules for control of toxic air pollutants, including a list of all TAP guidelines.

• Science Advisory Board Charter
• Priorities for SAB Review of Toxic Air Pollutants
• Practices and Policies for the SAB
• SAB Risk Assessment Guidelines

SAB meetings are open to the public and participation by interested groups is not only allowed, but encouraged. The Toxics Protection Branch staff is responsible for coordinating the SAB meetings; to obtain more information about upcoming SAB meetings, please contact Robin Barrows at (919) 707-8445 or robin.barrows@ncdenr.gov.

Science Advisory Board Recommendations

SAB Review of Mercury in the Environment (Large Document; ~1.25 MB) [PDF]  [Text]

After a two year effort, the SAB is preparing to issue their findings concerning the toxicity of mercury, ongoing exposure levels in North Carolina and the environmental impact of mercury emissions to the air. Their findings will highlight conclusions that can be made from the available data as well as uncertainties that remain on several important issues. They will also specifically respond to the request to develop an AAL for mercury that accounts for indirect (non-inhalation) routes of exposure. The SAB owes a debt of gratitude to over a dozen expert speakers that volunteered their time to interact with the Board. It was these contributions that allowed the SAB to progress forward on many challenging topics.

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