Exposure limits for hazardous substances may be set by the Authority under the HSNO Act and Regulations to limit exposure of people, to limit exposure of the environment, and to control exposure in places of work. They are enforceable controls, applied to new substances when they are approved under Part V of the Act and to existing substances when they are transferred to the Act.
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Tolerable Exposure Limits (TELs) Limiting exposure to people. |
Tolerable exposure limits (TELs) limit public exposure to toxic substances. They do not apply to a place of work if the public does not have access to that place. Toxic substances are those with a HSNO classification in Class 6. A TEL is the maximum concentration of a hazardous substance legally allowable in a particular environmental medium - i.e. air, water, soil or a surface that the substance may be deposited onto. TELs are derived from potential daily exposure (PDE) values, which in turn are derived from acceptable daily exposure (ADE)/reference dose (RfD) values. The circumstances under which TELs are set are described in the Hazardous Substances (Classes 6, 8 and 9 Controls) Regulations 2001 (Part 2). |
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Environmental Exposure Limits (EELs) Limiting exposure to ecotoxic substances. |
An environmental exposure limit (EEL) establishes the maximum concentration of an ecotoxic substance legally allowable in a particular environmental medium (e.g. water, soil or sediment), including deposition of a substance onto surfaces (e.g. as in spray drift deposition). Ecotoxic substances are those with a HSNO classification in Class 9. EELs apply outside an application area, and in the case of discharges to water apply after reasonable mixing. Only 1 environmental exposure limit for a class 9 substance may apply to an environmental medium at any given time or in any given circumstance. The circumstances under which EELs are set are described in the Hazardous Substances (Classes 6, 8 and 9 Controls) Regulations 2001 (Part 3). Note: Resource consent requirements set by regional councils may be more stringent than the HSNO requirements, but not less restrictive. The proviso is that existing resource consents are not affected by HSNO until they are subject to review under section 128 of the Resource Management Act 1991. |
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Controlling exposure in places of work Workplace Exposure Standards (WESs). |
A workplace exposure standard (WES) is designed to protect persons in the workplace from the adverse effects of toxic substances. A WES is an airborne concentration of a substance (expressed as mg substance/m3 of air or ppm in air), which must not be exceeded in a workplace and only applies to places of work to which the public does not have access. The circumstances under which WESs are set are described in the Hazardous Substances (Classes 6, 8 and 9 Controls) Regulations 2001 (regulations 29-30). The Occupational Health and Safety Service (OSH) of the Department of Labour is the primary agency responsible for setting workplace exposure standards. Their current list of standards may be obtained from their website at http://www.osh.dol.govt.nz . Current list of WESs set under the HSNO Act. (Links to DoL website) |
For further information see Compliance FAQs.