Using the E-Limit search tool and frequently asked questions

An exposure limit for a chemical or biological substance is the maximum airborne concentration to which it is believed workers may be repeatedly exposed over a working lifetime without adverse health effects.

Exposure limits in B.C. are regulated and administered by WorkSafeBC. All employers under WorkSafeBC's jurisdiction must ensure that no workers are exposed to chemical substances exceeding the B.C. exposure limits.

WorkSafeBC has exposure limits for about 800 substances, provided in the Table of Exposure Limits for Chemical and Biological Substances . It can be difficult to search the table and find the relevant information you need, particularly when using a mobile device. To assist with this type of search, WorkSafeBC has developed E-Limit.

Key features of the E-Limit search tool:

  • Searchable by multiple parameters
  • Central data source
  • Optimized for mobile devices, but can also be used on a desktop or laptop
  • Search results show complete information on one page

E-Limit is not designed to replace the judgment of qualified professionals - always consult an occupational hygienist or an occupational health and safety professional if you require assistance in interpreting an exposure limit. The tool is not intended to provide guidance on control measures to eliminate or minimize exposures in the workplace. E-Limit is designed specifically for British Columbia and does not include the regulatory exposure limits for other jurisdictions.

The Exposure Limits webpage on worksafebc.com contains more information about exposure limits and how they are determined.

How to use E-Limit

E-Limit is a searchable database of B.C. exposure limits and can be used to search for information about any substances included in the Table of Exposure Limits.

The following data is provided for each substance:

  • Chemical name (e.g., asbestos, lead)
  • Chemical Abstracts Service (CAS) number
  • B.C. exposure limits (TWA, STEL, and/or ceiling limit) and adverse health effects the exposure limits are intended to minimize
  • Health hazard notations or designations (e.g., cancer, sensitizer, reproductive toxin, 2A, IARC)
  • Immediately dangerous to life or health (IDLH) values
  • Regulatory requirements
  • Definitions for key terms
  • Common synonyms and chemical formulae for selected substances

Search tips

  • To get the most accurate results, type in the full substance name into the search box (e.g. allyl chloride).
  • For CAS numbers, type in the entire CAS number (e.g., either 50000 or 50-00-0).


  • Click on the word "E-Limit" to get back to the home page.
  • Your search will display a list of up to 10 substances per page. If your search yields more than 10 results, you can use the drop-down arrow to change how many results that you would like to view per page.

Frequently Asked Questions

Chemical and biological substances may have one or more of the following types of exposure limits:

  • TWA - the time weighted average concentration of a substance in air which may not be exceeded over a normal 8-hour work period
  • STEL - short-term exposure limit, the time weighted average concentration of a substance in air that may not be exceeded over any 15-minute period, limited to no more than 4 such periods in an 8-hour work shift with at least one hour between any 2 successive 15-minute excursion periods
  • Ceiling limit - the concentration of a substance in air that may not be exceeded at any time during the work period

Visit our Exposure Limits webpage for information.

E-Limit is a centralized data source, drawing information from the following:

  • Occupational Health and Safety Regulation
  • Occupational Health and Safety Policy items
  • Occupational Health and Safety Guidelines
  • American Conference of Governmental Industrial Hygienists (ACGIH)
  • International Agency for Research on Cancer (IARC)

E-Limit includes a glossary of terms and notations.

Yes, although E-Limit is optimized for mobile devices, it is a web app, not a mobile app, so you will need internet access to use it.

No, E-Limit's search function cannot perform wildcard or Boolean searches. E-Limit also does not allow searching by any of the following:

  • Numerical value of a B.C. exposure limit
  • Word fragments with too few letters
  • Tradenames, most common names, or generic names (e.g. paint, alcohol, Difolatan)

If two dashes "- -" appear in one of the exposure limit rows (TWA, STEL, and/or Ceiling Limit), it indicates there are no current B.C. exposure limits for this substance. For some substances, the "Notes & Notation" section has further information.

LEL values are not included in the tool, but the notation "EX" indicates that the substance is a flammable asphyxiant or that excursions above the exposure limit could approach 10% of the lower explosive limit.

E-Limit does not have a download or export function, but you can either print the page or copy your search results and paste them into another file format (e.g., a word processing file) to save or print.

For assistance in applying an exposure limit, consult with a qualified professional or call the WorkSafeBC Prevention Information Line: 604.276.3100 (Lower Mainland) or 1.888.621.7233 (1.888.621.SAFE) (toll-free in Canada).

For technical issues, please contact our Technical Support Desk.

We appreciate your ideas and feedback. Please email our team at elimit@worksafebc.com