Chapter 173-401 WAC
Air Operating Permit (AOP) Rule
Overview of Rulemaking
On February 3, 2016, Ecology adopted amendments to Chapter
173-401 WAC Operating Permit Rule. The amendments:
- Update language for the complexity portion of
Ecology’s air operating permit (AOP) fees to allow for
fair fee distribution to Ecology AOP sources.
- Revise audit provisions.
- Clarify applicability requirements.
- Clarify rule provisions, update language to be
consistent with state and federal rules, and correct
What is Chapter 173-401 WAC, Operating Permit
Title V of the federal Clean Air Act requires states to develop
and implement an air operating permit program for facilities that are
the largest sources of air pollution. These operating permits are often
referred to as Air Operating Permits (AOPs), Title V Permits, or Part 70
Permits. They combine into one document the requirements for operations,
procedures, applicable rules, emissions standards, monitoring,
recordkeeping, and reporting. The purpose of the AOP is to make it
easier to comply with and enforce air pollution laws.
Chapter 173-401 WAC establishes Washington’s air operating
permit program. The rule requires a facility to have an AOP if it
has the potential to emit any of the following:
- More than 100 tons per year of any
pollutant such as nitrogen oxides (NOx), volatile
organic compounds (VOCs), carbon monoxide (CO), sulfur
dioxide (SO2), and particulate matter (PM). Lower
thresholds may apply in nonattainment areas;
- More than 10 tons of any hazardous air
pollutant (HAP) as listed in subsection 112(b) of the
federal Clean Air Act; or
- More than 25 tons per year of a combination of
A facility may also be required to have an AOP
if it is subject to certain federal air quality
- Title IV Acid Rain Program;
- New Source Performance Standards (NSPS); or
- National Emission Standard for Hazardous Air
Who does this rule affect?
It affects a broad range of industries and facilities required
to have an AOP as defined in Chapter 173-401 WAC.
This adoption can be appealed under procedures described in the
Administrative Procedure Act (RCW 34.05.330). For more information
about appealing this rule adoption, please contact Bari Schreiner,
Agency Rules Coordinator, at (360) 407-6998 or