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Chapter 173-460 WAC

This rulemaking will amend Chapter 173-460 WAC, Controls for New Sources of Toxic Air Pollutants.  This rule includes air quality permitting requirements for businesses that emit toxic air pollutants.

The rulemaking will use the most recent, best available health effects information to:

  • Update the list of toxic air pollutants.
  • Recalculate:
    • Acceptable source impact levels (ASIL)
    • Small quantity emission rates (SQER)
    • De minimis emission values
  • Update the rule to support the changes described above.

We are also starting a related, but different, process we call exploratory rulemaking to assess possible changes to the rest of Chapter 173-460 WAC.

Rulemaking timeline


Announcement phase (CR-101)

Filing date:
Jul. 18, 2018

Announcement documents

Rule development phase

July 18, 2018 – Spring 2019

Public input & involvement

Ecology's meetings with stakeholders
Date Documents Location
Aug. 20, 2018
10 a.m. – noon
Methods for Updating the List of Toxic Air Pollutants
2018 Draft Acceptable Source Impact Levels (ASIL) Summary List
2018 ASIL Options (spreadsheet)
Ecology, Lacey (map to location)
Oct. 10, 2018
1:30 p.m. – 3:30 p.m.
• Draft table
• Toxicity equivalency factors
• Early life adjustment factors
• Mercury
Ecology, Lacey (map to location)
webinar *
Nov. 16, 2018
1 p.m. – 3 p.m.
• Draft table
• Criteria pollutants
Ecology, Lacey (map to location)
webinar *
Dec. 11, 2018
1 p.m. – 3 p.m.
• Draft table
• Ammonium sulfate
Ecology, Lacey (map to location)
webinar *

* Register to receive your access code and password.
   To hear the webinar better, use your phone (instead of the computer) to call 1-240-454-0887.

Additional languages

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