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)
Meeting summary
Ecology, Lacey (map to location)
Oct. 10, 2018
1:30 p.m. – 3:30 p.m.
• Agenda
• Toxicity Equivalence and Early Life Adjustment Factors
• Dimethyl Mercury Inhalation Risk Screening Concentration
Ecology, Lacey (map to location)
webinar * (registration and instructions)
Nov. 16, 2018
1 p.m. – 3 p.m.
• Draft table
• Criteria pollutants
Ecology, Lacey (map to location)
webinar *
Dec. 10, 2018
10 a.m. – noon
• Ammonium sulfate
• Agenda
    • Ecology presentation
    • Far West Agribusiness Association presentation
    • Group discussion
Three Rivers Convention Center (directions)
7016 West Grandridge Boulevard, Kennewick
Call-in number:  360-407-3780
PIN code:  893108#

* Webinar information:
   Register for each webinar to get your access code and password.
   To hear the webinar better, use your phone (instead of the computer) to call 1-855-929-3239.
   Meeting number (access code) 805 434 126

Additional languages

Español (Spanish) 中文 (Chinese) Tiếng Việt (Vietnamese) 한국어 (Korean)


To request ADA accommodation for disabilities, or printed materials in a format for the visually impaired, call Sultana Shah at 360-407-6831 or email People with impaired hearing may call Washington Relay Service at 711. People with speech disability may call TTY at 877-833-6341.