Tier II Analysis Information

This web site is intended for those seeking information about what to expect when they need a Tier II Analysis for an air quality permit.

Select this link for a map of Tier 2 Documents

What is Tier II Analysis?

Tier II Analysis is the second of three levels of review done in making permit decisions for projects that emit toxic air pollutants (TAPs):

1) Tier One - Ecology or a local air quality agency screens the project to determine if it will emit TAPs

2) Tier II - Ecology determines health impacts of the emitted TAPs

3) Tier Three - Ecology determines how to best manage the health risks of the emitted TAPs

When are these different levels of analysis required?

Tier I: All projects must undergo Tier I Analysis (toxic screening) before getting a permit. This is required by WAC 173-460-040. The purpose of the toxic screening is to control emissions of TAPs from new sources in order to prevent air pollution, reduce TAP emissions as much as possible, and maintain healthy and safe air quality.

Tier II: If a project emits more of a listed TAP than is allowed by the Acceptable Source Impact Levels (ASIL) in Chapter 173-460 WAC ( http://apps.leg.wa.gov/WAC/default.aspx?cite ), Ecology must perform a Tier II Analysis. This analysis determines the increase in lifetime cancer risk and other health effects for persons exposed to increased amounts of a TAP as a result of the proposed project. The cancer and health risks are then compared to the maximum risk allowed by a Tier II Analysis to see if they are within allowable limits.

Tier III: If the emissions of a TAP result in a risk higher than allowed by the Tier II Analysis, a permit applicant may ask Ecology to perform a Tier III analysis. A Tier III Anaysis is basically a risk management decision. Ecology's Director decides whether the risk of the project is acceptable based on:

whether Ecology determined that available preventive measures can reduce emissions enough to protect human health;
estimated environmental effects; and
public input received at a public hearing, and related community feedback about the proposed facility.

What pollutants are considered TAPs?

Here is a link to a consolidated list of TAPs. Please see sections 150 and 160 of Chapter 173-460 WAC for more complete information about chemicals that are TAPs.

Who does the analyses?

Local air quality agencies routinely do Tier I Analyses. However, only Ecology does Tier II and III Analyses.

Please note:
For more information please contact Richard B. Hibbard at rhib461@ecy.wa.gov or (360) 407-6896. Comments can be mailed to the indicated Ecology contact, Washington Department of Ecology, P.O. Box 47600, Olympia, WA 98504-7600.

Related Link

Tier II Finals