ALLEGHENY COUNTY HEALTH DEPARTMENT AIR QUALITY PROGRAM
Policy for Air Toxics Review of Installation Permit Applications
Final Committee Proposal – May 25, 2012
The Board of Health will take up this air toxics proposal at its next meeting on September 5, 2012. Allegheny County residents can comment on the proposal in writing only. The Allegheny County Health Department’s address is: 3901 Penn Ave., Building 7, Pittsburg, PA 15201. Letters should be addressed to the Air Quality Division.
I. PURPOSE This document establishes the policy the Allegheny County Health Department Air Quality Program (the Department), will use for evaluating the human health impacts of new or significantly modified sources emitting toxic air emissions into the ambient air. This policy document is effective until modified by the Department or until formal rules are promulgated. This policy does not change any federal, state or County requirements including, but not limited to, all Best Available Control Technology (BACT), New Source Performance Standards (NSPS), National Emission Standards for Hazardous Air Pollutants (NESHAPS), New Source Review (NSR), Prevention of Significant Deterioration (PSD) and Allegheny County Health Department Rules and Regulations, Article XXI, Air Pollution Control (Article XXI). There is no intent on the part of the Department to give this policy the weight or deference of a regulation. This document establishes the framework for the Department to exercise its administrative discretion in the future. The Department reserves the discretion to deviate from this policy statement if circumstances warrant.
II. APPLICABILITY This policy applies to all applications for an Installation Permit (IP) required under the provisions of Article XXI, including new facilities, modifications to existing facilities, or addition of new equipment that are expected to increase the net potential air toxics emissions from the facility into the ambient air. For the purpose of this policy, “air toxics” are those pollutants defined as “air-borne pollutants that are known or suspected to cause cancer or other serious health effects, such as reproductive effects or birth defects, respiratory illness, neurological effects, or to cause adverse environmental effects that are predictive of adverse human health consequences.”
III. AUTHORITY With few exceptions, any person installing, modifying, replacing, reconstructing, or reactivating a source of air pollution or air pollution control equipment within the County must first obtain an IP from the Department. Article XXI § 2104.04.b.7 states, “The Department shall not issue any Policy for Installation Permit unless it has . . . received a complete application meeting the requirements of this Part, which application includes or demonstrates that: . . . Emissions from the proposed source will not endanger the public health, safety, or welfare. . . “ This policy specifies the guidelines which the Department will use to determine whether the application sufficiently demonstrates that the proposed installation will not endanger the public health, safety and welfare of Allegheny County.
IV. GUIDELINES Prior to issuing an IP applicable to this policy, the Department will require the applicant to perform: a) an analysis of the carcinogenic health effects of air toxic emissions; and b) an analysis of the non-carcinogenic health effects of air toxic emissions.
a. Analysis of Carcinogenic Health Effects The IP application should contain an analysis demonstrating to the Department’s satisfaction that the combined impact of the proposed increased potential air toxic emissions with known or possible carcinogenic health effects does not result in an aggregated Maximum Individual Carcinogenic Risk (MICR) of greater than 1 x 10-5 (one in one hundred thousand) beyond the fence-line of the facility. For the purposes of this policy, MICR is defined as the probability of developing cancer by an individual exposed to the expected concentrations of all substances in the ambient air over a 70-year period aggregated over the proposed increased potential air toxic emissions. The aggregated MICR for a mixture of substances is equal to the sum of the MICRs for each individual substance.
If the MICR from the proposed IP is less than 1 x 10-5 beyond the fence-line, taking into account both the IP and offsets from the facility and nearby existing sources, the Department will approve the carcinogenic risk analysis and no further assessment for carcinogenic effects will be required.
If the MICR from the proposed IP plus other nearby existing permitted sources is greater than 1 x 10-4 (one in ten thousand) beyond the fence-line, the Department will not approve the IP. In making this determination, the Department shall consider offsets from the facility of the proposed IP and other nearby existing sources.
If the MICR from the proposed IP is greater than 1 x 10-5 but less than 1 x 10-4, beyond the fence-line, taking into account both the IP and offsets from the facility and other nearby existing sources, the Department will require an emissions modeling analysis that includes the potential emissions from the proposed IP, emission offsets from the facility and other nearby existing sources, actual emissions from all other sources in applicant’s entire facility, and actual emissions from other nearby existing permitted sources that are expected to have a significant effect. The Department will assess the public health risk and may require additional actions to reduce risk. Such actions may include, but are not limited to: ambient air monitoring, more stringent emission controls, controls at other sources within the facility, or additional offsets.
b. Analysis of Non-Carcinogenic Health Effects The IP application should contain an analysis demonstrating to the Department’s satisfaction that the increased ambient concentration of any individual air toxic resulting from the proposed increase in potential air toxic emissions with known or possible non-carcinogenic health effects will not exceed the Reference Concentration (RfC) beyond the fence-line of the facility. For the purposes of this policy, RfC is the continuous inhalation exposure concentration of a substance that is likely to be without an appreciable risk of adverse health effects to the human population (including susceptible subgroups) over a lifetime.
If the proposed installation results in potential increases of multiple air toxics, the IP application should contain an analysis calculating the Cumulative Hazard Index (HI). For the purposes for this policy, the HI is defined as the sum of the Hazard Quotients (HQ) for substances that affect the same target organ or organ system. The HQ is defined as the ratio of the expected air toxic concentration to its corresponding RfC.
If the HI from the proposed IP is less than 2.0 beyond the fence-line, taking into account both the IP and offsets from the facility and other nearby existing sources, the Department will approve the non-carcinogenic risk analysis and no further assessment of non-carcinogenic effects will be required.
If the HI from the proposed IP plus other nearby existing point sources is greater than 2.0 beyond the fence-line, the Department will require an emissions modeling analysis that includes the potential emissions from the proposed IP, emission offsets from the facility and other nearby existing sources, actual emissions from all other sources in applicant’s entire facility, and actual emissions from other nearby existing permitted sources that are expected to have a significant effect. The Department will then assess the public health risk and may require additional actions to reduce risk. Such actions may include, but are not limited to: ambient air monitoring, more stringent emission controls, controls at other sources within the facility, or additional offsets.
V. SOURCES OF TOXICITY INFORMATION The best available federally-recognized and peer reviewed science should be used to conduct health assessments required by this policy. In general, if health assessment information is available in EPA’s Integrated Risk Information System (IRIS) for the air toxics under evaluation, there is no need to search further for additional sources of information.
If such information is not available in IRIS, Unit Risks (for carcinogens) or Chronic Reference Exposure Limits (for non-carcinogens) from the California Environmental Protection Agency (Cal EPA) should be used, as specified in current EPA guidance documents. In the absence of RfC information from IRIS or CalEPA for a particular pollutant for non-carcinogenic effects, the analyses are to use American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values Time Weighted Average concentrations (TLV-TWAs). If TLV-TWA’s are used for a pollutant, they must be converted to a 24-hr, seven day-per-week averaging time and include an appropriate factor for sensitive populations.
VI. EMISSION OFFSETS If the applicant for an IP is unable to demonstrate to the Department’s satisfaction that emissions from the proposed installation meet the guidelines defined in this policy, the IP may still be approved if the applicant secures a sufficient amount of Emission Offsets (Offsets) as defined in this policy. However, the Department will not approve an IP through the use of Offsets generated by reductions outside of the applicants facility or nearby facility if the combined impact of air toxics emitted from the installation and nearby point sources as determined by the Department with known or possible carcinogenic health effects results in a MICR greater than 1 x 10-4 (one in ten thousand) beyond the fence line of the facility.
For the purposes of this policy, Offsets are defined as reductions in air toxics emissions at existing sources (including mobile sources) within Allegheny County that may be used to compensate for the emissions resulting from the installation proposed in the IP. Unless specified differently in this policy, Offsets will be subject to similar offset requirements contained in Article XXI §2102.06.b.4. Generally, Offsets must be made legally binding by a Department order or permit condition and actually occur no later than the date on which the IP’s proposed installation commences operation (exclusive of any Department approved shakedown period for replacement units). The reductions shall be maintained throughout the operating life of the sources for which the IP was issued. Offsets cannot be created from emissions reductions required by Federal, State, or Article XXI requirements or reductions made more than five years prior to the date of the IP application.In addition, credit for Offsets cannot be taken for potential emissions which were never achieved or emitted, or for reductions that have been used for previous IP’s.
a. Required Offsets for Emissions with Carcinogenic Health Effects The ratio of actual air toxics emission reductions to new emissions shall be greater than or equal to the applicable ratio specified in Table I. It is not necessary that the emission reductions be the same air toxics pollutant as the new emissions. However, when different pollutants are involved, each Offset Ratio shall be calculated for each offsetting pollutant using the following equation: OR = ORT1 x (URFe/URFr) Where: OR = Required Offset Ratio ORT1= Offset Ratio from Table I URFe=Unit Risk Factor of the pollutant in the new emissions (from data sources in Section V) URFr=Unit Risk Factor of the pollutant in the reduction (from data sources in Section V)
Table I Offset Ratios Location of Emission Reduction Ratio or Emission Reduction to New Emissions
Within the Same Facility as the IP 1 to 1
Other Locations in Allegheny County 1.15 to 1
Mobile Sources in Allegheny County 1.5 to 1
b. Required Offsets for Emissions with Non-Carcinogenic Health Effects Applicants may offset air toxics emissions with non-carcinogenic health effects at the ratios specified in Table I. However, the emission reductions must be the same air toxics pollutant as the new emissions.
VII. DEVIATIONS The Director of the Allegheny County Health Department may approve deviations from this policy if it is determined that the proposed increase in potential emissions of air toxics has been controlled to the maximum practical amount and does not pose an unacceptable human health risk. Any deviations must be approved in writing and documented in the Technical Support Document of the applicable IP.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~