NORTHERN SONOMA COUNTY AIR POLLUTION CONTROL DISTRICT

RULE 225 - TOXICS REVIEW STANDARDS

225.1 Purpose

This Rule is intended to provide a framework for the review of toxic or hazardous emissions from stationary sources of air pollution. The Rule is intended to accomplish three goals. First, it requires review and control of toxic or hazardous emissions from new, reconstructed, and modified sources; control requirements are based on the degree of risk to the public from exposure to the emissions from the source. Second, the Rule establishes the thresholds for action under the California Air Toxics Hot Spots Act; the District is required to identify these thresholds under the California Health & Safety Code, Sections 44360, 44362(b), and 44391(a). Third, the Rule requires emissions control on new and reconstructed major sources of Hazardous Air Pollutants, in accordance with the requirements of Section 112(g) of the federal Clean Air Act. These three review processes will be carried out as part of the preconstruction review already required under District Regulation 1, Rule 200, and under the annual permit review required in District Regulation 1, Rule 240.


225.2 Applicability

This Rule shall apply to all owners or operators of stationary sources that emit toxic or hazardous air pollutants. Compliance with this Rule does not relieve any owner or operator of any stationary source from complying with all other District Rules or Regulations, any applicable California Airborne Toxic Control Measure (ATCM), National Emission Standard for Hazardous Air Pollutants (NESHAP), or other applicable State or Federal laws.


225.3 Exemptions

The APCO may find, through public notice and comment, that a category or subcategory of sources of toxic or hazardous air pollutants has a sufficiently small potential to expose the public to significant health risks, and may exempt such category or subcategory from further review under this Rule. No major source of hazardous air pollutants shall be exempted from the requirements of this Rule.


225.4 Definitions

A1. Air Toxic Control Measure means a requirement to reduce emissions of one or more toxic air contaminants developed pursuant to the California Health and Safety Code Section 39600.

A2. Additional Mitigation of Risk means any measures which will further reduce or eliminate the health risk associated with emissions of toxic air contaminants, are real, permanent, quantifiable and enforceable through District permit conditions if applicable.

A3. Alternative Control Plan means a plan which allows a source to demonstrate an alternative method of Rule compliance or compliance with an emission limitation.

B1. Best Available Control Technology for Toxics (TBACT) means the most stringent emissions limitation or control technique which:

(a) has been achieved in practice for such permit unit category or class of source; or
(b) is any other emissions limitation or control technique, including process and equipment changes of basic and control equipment, found by the Air Pollution Control Officer to be technologically feasible for such class or category of sources, or for a specific source.


C1. California Air Pollution Control Officers Association (CAPCOA) means the official association of which the air pollution control officers and executive officers of the local air pollution control districts and air quality management districts in California are members.

D1. De minimis means any emission level of toxic or hazardous air pollutants which is expected to result in an increase in the maximum individual cancer risk to the exposed public of less than or equal to one in one million, or an increase in non-cancer risk less than or equal to a Hazard Index of 1.

E1. Emission Unit means any identifiable article, machine, contrivance, or operation, which emits, may emit, or results in the emissions of, any toxic or hazardous air pollutant.

F1. Facility means the emission unit, or aggregated emission units including fugitive emissions, which comprise the stationary source.

F2. Fugitive Emissions means those emissions from a stationary source that could not reasonably pass through a stack, chimney, vent or other functionally equivalent opening.

H1. Hazard Index (HI) means the annual average concentration divided by the applicable chronic exposure level or the maximum hourly concentration divided by the applicable acute reference exposure level for toxic or hazardous air contaminants.

H2. Hazardous Air Pollutant (HAP) means any air pollutant listed as a hazardous air pollutant pursuant to section 112(b) of the federal Clean Air Act. Appendix (B) contains the current list of HAPs.

H3. Health Risk Assessment means a detailed comprehensive analysis prepared pursuant to CA H&SC Section 44361 to evaluate and predict the dispersion of hazardous substances in the environment and the potential for exposure of human populations and to assess and quantify both the individual and population wide health risks associated with those levels of exposure.

M1. Major Source of HAP(s) means any stationary source or functionally separate emission unit at a stationary source, which emits or has the potential to emit at least 10 tons of any single HAP per year, or 25 tons of any combination of HAPs per year.

M2. Maximum Achievable Control Technology (MACT) means emission controls or limitations included in any NESHAP promulgated under 40 CFR Part 63, or any case-by-case determination of emission control or limitation established pursuant to Section 112 of the federal Clean Air Act.

M3. Maximum Individual Cancer Risk is the estimated probability of a potentially maximally exposed individual contracting cancer as a result of exposure to toxic or hazardous air pollutants over a period of 70 years.

O1. Office of Environmental Health Hazard Assessment (OEHHA) means the office of the California Environmental Protection Agency which reviews scientific data, methods, and analyses used in establishing health risks to the public from exposure to toxic or hazardous substances.

P1. Pollution Prevention means any technique, including process redesign, material substitution, reuse or regeneration, which results in lower emissions of air pollutants prior to the application of control technology. Pollution Prevention does not include shut down of equipment in and of itself, unless such shutdown occurs as a result of the aforementioned activities.

P2. Potential to Emit means the maximum quantity of toxic air contaminants, including fugitive emissions, that a project or emission unit is capable of emitting considering physical and operational design. Any physical or operational limitation on the capacity of the emissions unit to emit a pollutant, including air pollution control equipment and restrictions on hours of operation or on the type of material processed, combusted or stored shall be considered if the limitation is federally enforceable.

P3. Prioritization Score means the numerical representation of relative importance of further review of health risks from a stationary source or project. The Prioritization Score is based on the quantity and toxicity of emissions from the source, and the distance from the source to the nearest offsite location where a person may experience either occupational or residential exposure to such emissions, or other considerations consistent with the CAPCOA Guidelines for Prioritization.

P5. Project means an emission unit or aggregation of emission units located at a stationary source for which an application or combination of applications for an Authority to Construct or modified Permit to Operate is under District review.

R1. Reasonable Control Technology (RCT) means the lowest emission limitation that a particular source is capable of meeting by the application of control technology that is reasonably available considering technological and economic feasibility.

R2. Reconstruction means the replacement of equipment at a stationary source such that the fixed capital cost of the new equipment exceeds 50 % of the fixed capital cost that would be required to construct a comparable stationary source.

R3. Reference Exposure Level (REL) means the ambient concentration of a toxic or hazardous air pollutant below which no adverse non-cancer effects are expected to result. The REL is established for a given toxic or hazardous air pollutant by OEHHA.

S1. Screening Risk Assessment means an evaluation of the potential adverse health effects from exposure to environmental hazards. The evaluation shall include a description of the facility, identification of the substances emitted, individual excess cancer risk for the maximum exposed individual, estimation of maximum potential excess cancer burden, a comparison of acute and chronic exposure levels to the OEHHA reference exposure levels, identification of the CAPCOA Risk Assessment Guideline version by date which was used to prepare the risk assessment and appendices containing all calculations and dispersion modeling printouts.

S2. Source means any emission unit or grouping of emission units at a stationary source, including fugitive emissions associated with such emission unit(s), that emit or have the potential to emit toxic or hazardous air pollutants.

T3. Toxic Substance means any substance listed under the Emission Inventory Criteria and Guidelines adopted pursuant to the Air Toxics "Hot Spots" Information and Assessment Act of 1987 or any substance listed under section 112(b) of the federal Clean Air Act.


225.5 Standards

This section contains standards, which apply in three distinct instances. The first section (225.5.1) contains requirements for control of emissions from new, reconstructed, or modified sources, based on the estimated risk to the public. The second section (225.5.2) establishes the circumstances when a Health Risk Assessment must be prepared for an existing source, and risk levels at which the public must be notified, and the risks reduced. The third section (225.5.3) details the requirement for a new or reconstructed major source of Hazardous Air Pollutants to install Maximum Achievable Control Technology prior to operation of the source.

225.5.1 Review of Health Risks from New, Reconstructed, and Modified Sources: No person shall construct, reconstruct, or modify a source of toxic or hazardous air pollutants without first submitting an application to the APCO for review of such emissions pursuant to this section, and obtaining an Authority to Construct the project. Section 225.5.1 applies only to new, reconstructed, or modified sources. Section 225.5.1 applies only if the toxic or hazardous air pollutants emitted are listed by the APCO in the District Manual of Procedures, and if the emissions are greater than any de minimis emission rate listed for the pollutant. The control requirements of Section 225.5.1 are tiered; the first level applies in all cases, and subsequent levels apply only if the estimated health risks meet the threshold for the requirement. This section is intended to implement the review described in the California Health and Safety Code Section 39666(e).

  1. Reasonable Control Technology (RCT)- The owner or operator shall install RCT on the project being constructed, prior to start-up of the project.

  2. Best Available Control Technology for Toxics (TBACT)- The owner or operator shall install TBACT on the project being constructed, prior to the start-up of the project, if a District-approved screening risk assessment finds the health risks meet either of the following criteria:

    1. Project Risks: The emissions from the project result in a maximum individual cancer risk greater than or equal to 1 in a million, or a non-cancer risk greater than or equal to a total Hazard Index of 1; or

    2. Facility Risks: The cancer risks from the facility are greater than or equal to 10 in one million, or the non-cancer risks from the facility are greater than or equal to a total Hazard Index of 10.

  3. Additional Mitigation of Risk (AMR)- The owner or operator shall propose AMR prior to the construction of the project, if a District-approved screening risk assessment finds that emissions from the project may result in a maximum individual cancer risk greater than or equal to 10 in one million, or a total hazard index of 10.

  4. Unacceptable Health Risks- No person may construct, reconstruct, or modify a source of toxic or hazardous air pollutant emissions if such emissions may result in an unacceptable risk to the public. An Unacceptable Health Risk is any estimated health risk that meets either of the following criteria:

    1. Unacceptable Cancer Risk: Any maximum individual cancer risk equal to or greater than 100 per million; or,

    2. Unacceptable Non-cancer Risk: Any Hazard Index equal to or greater than 10, unless, following a case-by-case, pollutant specific review, the APCO finds that a higher Hazard Index is acceptable.

  5. Alternative Requirements- Any person required to comply with the requirements of Section 225.5.1 may submit an alternative to those requirements as outlined below in 225.5.1 E.1 and E.2, below:

    1. Alternative Control Plan (ACP)- Any person required to install RCT or TBACT pursuant to Sections 225.5.1 A or B may submit an Alternative Control Plan to the APCO for approval. Any ACP submitted under this section must meet the requirements established in the District Manual of Procedures.

    2. Refined Health Risk Assessment- Any person proposing to construct, reconstruct, or modify a source where the District-approved screening risk assessment finds impacts greater than or equal to a cancer risk of 10 in a million or a total Hazardous Index of 10, may submit a more refined Health Risk Assessment (HRA), provided such submittal meets the criteria established in the District Manual of Procedures.

225.5.2. Review of Health Risks from Existing Sources:

Any person who operates a source of toxic or hazardous air pollutants shall identify, inventory, report, publicly notice, and reduce such emissions as required under the California Health and Safety Code, Sections 44300 through 44394. Procedures for implementing these requirements are established in the District Manual of Procedures. Section 225.5.2 establishes the action levels for the preparation of a Health Risk Assessment (HSC Section 44360), the notification of risks (HSC Section 44362(b)) and the reduction of risks (HSC Section 44391(a)).

  1. Assessment of Potential Health Risks- Any person who operates a source of toxic or hazardous air pollutants shall prepare a Health Risk Assessment, in accordance with the District Manual of Procedures, and the following criteria:

    1. Low Priority Facilities: A Low Priority Facility is any facility with a District-approved Prioritization Score less than or equal to 1. Low Priority Facilities are not required to prepare a Health Risk Assessment.

    2. Intermediate Priority Facilities: An Intermediate Priority Facility is any facility with a District-approved Prioritization Score greater than or equal to 1, and less than 10. An Intermediate Priority Facility shall prepare and submit a Health Risk Assessment if requested to do so by the District.

    3. High Priority Facilities: A High Priority Facility is any facility with a District-approved Prioritization Score greater than or equal to 10. A High Priority Facility shall prepare and submit a Health Risk Assessment within 150 days of notification by the District that it is a High Priority Facility.

  2. Notification of Risks- Any source where a District-approved Health Risk Assessment finds Reportable Health Risks must notify the public of such risks, in accordance with the District Manual of Procedures. A Reportable Health Risk is any risk that meets either of the following criteria:

    1. Reportable Cancer Risk: Any maximum individual cancer risk equal to or greater than 10 in one million; or,

    2. Reportable Non-cancer Risk: Any total Hazard Index equal to or greater than 10.

  3. Risk Reduction- Any source where a District-approved Health Risk Assessment finds Unacceptable Health Risks must submit and implement a plan to reduce these risks within 5 years to below the levels established as "unacceptable." The plan shall be prepared in accordance with the District Manual of Procedures, and submitted within 180 days of notification by the District that risks are "unacceptable." An Unacceptable Health Risk is any risk that meets either of the following criteria:

    1. Unacceptable Cancer Risk- Any maximum individual cancer risk equal to or greater than 100 in one million; or,

    2. Unacceptable Non-cancer Risk- Any total Hazard Index equal to or greater than 10, unless a case-by-case, pollutant specific review by the APCO finds that a higher Hazard Index may be acceptable.

225.5.3 Review of New or Reconstructed Major Sources of Hazardous Air Pollutants (HAPs):

Any new or reconstructed major source of HAPs shall install Maximum Achievable Control Technology on the major source prior to operation of the source. Section 225.5.3 applies only to sources that have the potential to emit 10 tons per year of any single HAP, or 25 tons per year of any combination of HAPs, as listed under Section 112(b) of the federal Clean Air Act. Section 225.5.3 implements the requirements of Section 112(g) of the federal Clean Air Act, as they apply to new or reconstructed major sources.

  1. EXEMPTIONS: The provisions of Rule Section 225.5.3 do not apply to any stationary source specifically exempted in 40 CFR Part 63.40 (b), (c), (e), and (f).
  2. CALCULATION PROCEDURES: The potential to emit for a source of HAP emissions shall equal the sum of the potentials to emit of the constructed or reconstructed source of HAPs. All fugitive HAP emissions associated with the construction or reconstruction shall be included in the potential to emit determination.
  3. ADMINISTRATIVE PROCEDURES
  1. An application for authority to construct a major source or reconstruct a major source of HAPs shall be subject to the administrative procedures contained in District Rule 220(b).

  2. Any person who owns or operates a major source of HAP for which a MACT determination has been approved shall, within one year of start-up of such source, apply for a Title V permit, or revision to the existing Title V permit for the stationary source.

225.6 Procedures

225.6.1 General Procedures: Procedures to carry out the requirements of this Rule are contained in the District's Manual of Procedures. The review processes of Sections 225.5.1, 225.5.2, and 225.5.3 will be carried out during the course of permit review otherwise mandated under District Regulation 1, Rules 200 and 240.

225.6.2 Schedules and Timelines for Review: In addition to the timelines established in District Regulation 1 for permit review, the following schedules and timelines apply:

  1. If an application is determined to be subject to Additional Mitigation of Risk, Alternative Control Plan, and/or a Health Risk Assessment, the APCO shall within 180 days following the acceptance of the application as complete, or a longer time period agreed upon, take final action on the application after considering all public comments.
  2. If an application is determined to be subject to Additional Mitigation of Risk, Alternative Control Plan or a Health Risk Assessment after being determined to be complete for the initial permit review, the application shall be deemed incomplete until all additional information needed to review the Additional Mitigation of Risk, Alternative Control Plan or Health Risk Assessment is received. The APCO shall within 60 days following the initial completeness determination notify the applicant if any provisions of this section become applicable.


225.7 Public N