HAP Rule 372Guidance

Permitting Division

Maricopa CountyAir Quality Department

HAP Rule 372Talking Points

• Rule overview and objectives

• Applicability

• Exemptions

• HAPRACT

• AZMACT

• Risk Management Analysis (RMA)

Maricopa County Air Quality DepartmentProtecting our most vital natural resource - air

HAP Rule 372Overview & Objectives

• Mitigate toxic impact

• Science based similar to NESHAP

• Identifies source categories specific to Arizona

• Mirrors state rule implemented by ADEQ

Maricopa County Air Quality DepartmentProtecting our most vital natural resource - air

HAP Rule 372Applicability

• Rule applies to new or modified sources of HAP (see

Section 102)

• Minor sources of HAP subject to HAPRACT if they are

listed in Table 1 (§102.1 - a)

• Major sources of HAP subject to AZMACT (§102.1 - b)

• Exemptions given in Section 103

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HAP Rule 372Exemptions

• Sources subject to a NESHAP under 40 CFR Part 61

and/or Part 63 (Section 100, §103.1)

• Sources that voluntarily accept NESHAP requirements

(§103.2)

• Sources that demonstrate any risk to be below

established standards by performing a RMA (Section

300, §306)

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HAP Rule 372HAPRACT

• Determination of HAPRACT must follow the sequence given in Section 300, §304.2 of the rule

• RACT definition in local Rule 100, §200.90 consistent with case-by-case approach in Rule 372

• EPA has established RACT to be “the lowest emission limit that a particular source is capable of meeting by the application of control technology that is reasonably available considering technological and economic feasibility” (see EPA memo of 1976, Roger Strelow and 44 FR 53761, September 17, 1979)

Maricopa County Air Quality DepartmentProtecting our most vital natural resource - air

HAP Rule 372AZMACT

• An emission standard that requires the maximum degree of

reduction in emissions of hazardous air pollutants… (definitions,

§205 of the rule)

• §305.2 of the rule requires a list of sources to determine the most

stringent emission limitation currently achieved in the U.S.

• Infeasible options are eliminated and the reasons documented

(§305.2)

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HAP Rule 372AZMACT (con’t.)

• The remaining options are evaluated sequentially in descending

order of removal efficiency (§305.2 - c)

• Each of the remaining options is evaluated considering economic,

environmental, and energy impacts pursuant to §305.2 - c & d

• Source proposes AZMACT in accordance with §305.2 - e

• AZMACT cannot be less stringent than NSPS at 40 CFR Part 60

or NESHAP at 40 CFR Part 61 (§305.3)

Maricopa County Air Quality DepartmentProtecting our most vital natural resource - air

HAP Rule 372RMA

• Applicant may demonstrate by performing a Risk Management Analysis (RMA) that HAPRACT or AZMACT are not necessary (§306.1 - a)

• RMA must use total potential to emit in accordance with §306.1 - c & d

• Applicant must conduct RMA for each pollutant emitted above the de minimis amounts (§306.1 - e & Table 2)

• Applicant may use any of the methods of §306.2 in performance of a RMA (tiers 1 - 4)

Maricopa County Air Quality DepartmentProtecting our most vital natural resource - air

HAP Rule 372Guidance

Permitting Division

Maricopa CountyAir Quality Department