Occupational Alliance for Risk Science

The Occupational Alliance for Risk Science (OARS) is an initiative to facilitate sharing of information with workers and occupational health and safety professionals. OARS provides a forum for information exchange about exposure guidance for chemical stressors, methods for improving occupational risk assessments, and training opportunities. The OARS serves as the home of exposure guide values, and related guideline documents, for chemical stressors. These guide values and supporting documentation related to worker and community exposure levels for chemical and physical agents and stressors are published by the OARS. OARS is managed by Toxicology Excellence for Risk Assessment (TERA).

View WEEL Database





  • New OARS WEEL for Menthol is now available. The OARS-WEEL for Menthol has been posted.



  1. WEEL™ Values now on-line! The Occupational Alliance for Risk Science - Workplace Environmental Exposure Levels (WEEL)™ are now available on-line from the OARS website, click here. An official press release was distributed on July 24, 2013.

  2. New Occupational Risk Assessment Course now available! TERA has developed an occupational risk assessment course on the development of occupational exposure limits (OELs). The course is a 4-day hand-on course offered thru OARS. Click here for more information.


  1. Alan Weinrich Scholarship for Studies in Occupational Health. Donations to the Alan Weinrich Scholarship for Studies in Occupational Health are now being accepted. For more information on how to donate to the scholarship fund, click here


TERA Forklift
Workplace Environmental Exposure Levels (WEELs)™ are health-based guide values for chemical stressors. The WEELs provide air concentrations intended to protect most workers from adverse health effects related to occupational chemical exposures.

Click here for the WEEL's table of values.


Occupational Alliance for Risk Science Sponsorship

There are two types of sponsorship. 

OARS Sponsorship: Grants intended to support the development and implementation of the Alliance mission. 

WEEL Sponsorship: Grants to support the development of a WEEL for a specific chemical stressor.

OARS Briefing Package (pdf)


If you are interested in becoming a sponsor for OARS, please contact Dr. Sue Ross at ross@tera.org or 513-542-7475 x21.

Click on image for a larger image (pdf).


OARS Mission

OARS is a collaborative initiative with the goal of promoting worker health protection through increased access to high quality occupational exposure limits, enhancements in methods for establishing worker-health exposure guidelines, and education and training in occupational risk assessment methods.


OARS Guiding Principles
A purpose of OARS is to prioritize and recommend Workplace Environmental Exposure Levels (WEELs)™ by:

bullet Communicating the basis for selection of candidate agents.

bullet Harmonizing methods to obtain and analyze relevant data.

bullet Defining a transparent process for development, approval and communication of


bullet Sharing resources effectively among organizations.


Presentations & Resources

The members of the OARS AAB make many presentations on various occupational and industrial hygiene topics. Click here to visit the webpage listing of these presentations.


OARS also has compiled a Resources Guide for OEL websites, methodologies and references. Click here for the Resource Guide (pdf).


Alliance Advisory Board

WEEL Committee






For any questions about OARS, please contact Dr. Sue Ross at ross@tera.org or 513-542-7475 x21.