Organisations & Regulations

There are three main areas of legislation regarding extraction equipment.

  1. The safety and suitability of the extractors is the responsibility of the manufacturer. In Europe this is covered by the CE marking requirements. America and Canada generally require equipment to be tested and approved to an appropriate international standard by UL, CSA or other approved test house. China and Japan have their own standard but will generally accept one of the above, as does most of the rest of the world.
  2. The safety of the workers using the equipment is the responsibility of the employer. The extraction equipment is normally used for local exhaust ventilation (LEV) to capture harmful dusts, fumes or vapours that if not captured would pose a health hazard to the operators. Legislation is in place in most countries to prevent exposure to harmful substances and to ensure equipment installed for this purpose is working correctly. The EU issues guidelines for Europe, but most European countries have their own occupational exposure limits (OEL's). In UK the Health and Safety Executive is the legislative body and the requirements are covered in the Control of Substances Hazardous to Health (COSHH) Regulations whilst the exposure limits are set out in the HSE booklet EH40.
  3. Hazardous waste is the responsibility of the end user. The particulate, fume or vapour captured by the filters in the extractor may cause the spent filters to be classified as Hazardous waste. In which case they will need disposing of in line with the appropriate legislation. In Europe this is covered by EU Directive 2008/98/EC.

For specific legislation information, please select a country from below:

Australia Austria Belgium Canada Denmark Estonia Finland France
Germany Hong Kong Ireland Italy Japan Luxembourg Mexico New Zealand
Norway Portugal South Africa Spain Sweden Switzerland UK USA


The Australian National Occupational Health and Safety Commission (NOHSC) sets OELs. The Commission consists of employee and employer organisations, trade unions, industry and government representatives. The Exposure Standards Expert Working Group (ESEWG) recommends OELs for individual substances.

A great number of the adopted exposure standards have been obtained from the ACGIH's (USA) list of threshold limit values. The National Commission has considered these values and those found to be acceptable were adopted. The Exposure Standards Working Group has reviewed a smaller number of substances in detail and appropriate values have been assigned.

The OELs are instruments of an advisory character, except where a law, other than the National Occupational Health and Safety Commission Act, or an instrument made under such a law, makes them mandatory. The application of any National Commission document in any particular State or Territory of Australia is the prerogative of that State or Territory.

More information on the Australian OSH regulations is available on the web site of the Australian and European Union Cooperation on Workplace Safety and Health.

Internet Links
NOHSC information
Australian and European Union Cooperation on Workplace Safety and Health


The Austrian OEL list is based on international and national sources such as the American Conference of Governmental Industrial Hygienists (ACGIH - see under USA for more details) and the German MAK-Commission. The Bundesministerium für Wirtschaft und Arbeit, or BMWA (Ministry of the Economy and Labour) fixes these limit values. The Austrian list is published in the Austrian Governmental Journal as an ordinance entitled "Grenzwerte für Arbeitsstoffe und über krebserzeugende Arbeitsstoffe" (Grenzwerteverordnung 2001 - GVK 2001) and on the Austrian pages of the European Agency. The "Sektion III - Zentral-Arbeitsinspektorat" (Central Labour Inspectorate) control their implementation.

Internet Links
Bundesministerium für Wirtschaft und Arbeit, (BMWA)


In Belgium, OELs are known as "Valeurs Limites d'Exposition Professionnelle" (VLEP) / or "Grenswaarden voor Beroepsmatige Blootstelling (GWBB).

Following the Royal decree of 10 August 1998 (Statute Paper of 12 September 1998), some of the Belgian OELs were changes to adapt to the European Union Guidelines, but the source of many OELs in Belgium is still the ACGIH (USA) TLV list. These OELs were fixed by the Ministry of Employment and Work. The Royal Decree of 3 May 1999 (Statute Paper of 7 December 1999) added a last column "C" for carcinogenic to relevant substances (Royal Decree of 2 December 1993, Statute Paper of 29 December 1993, with updates including carcinogenic substances of EC categories 1 and 2, labelled with Risk Phrases R45 or R49).

About 700 substances or groups of substances have one (TWA - 8h) or two (TWA - 8h and STEL - 15 minutes) binding and compulsory OELs in the appendix of the Royal Decree of 10 September 1998. It is in Appendix II of the "Règlement Général pour la Protection du Travail (RGPT)" or "Algemeen Reglement voor de Arbeidsbescherming (ARAB)". In the last column of this table can be found three other letter codes:

•M - for "Moment" or ceiling OEL that should not be exceeded during any part of working exposure
•D - for "Dermal" for where skin and/or eye absorption is an important issue
•A - for "Asphyxiant" or oxygen replacing agent.

Finally, the Royal Decree of 7 November 1998 (Statute Paper of 22 November 1988) introduces the atmospheric and biological limit values of metallic lead (Pb) and its compounds on the basis of the European Directive 82/605/EEC (RGPT, art. 148 decies 2).

Internet Links
The Belgian Ministry of Employment and Labour


Canadian autonomous regions have different OSH systems, which are applied according to the provincial regulations. The Provinces are also presented at the Canada - EU Co-operation site on Workplace Safety and Health.

Internet Links
An explanation on the Canadian OSH system
Canada - EU Co-operation site on Workplace Safety and Health
Ontario Legislation


The Regulation of the Quality of the Workplace deals with OELs, its appendix A contains a list of contaminants. The Joint Committee of the Board of the Directors of the Commission for Occupational Health and Safety revises the OEL list. There are employer and trade union representatives. The Joint Technical Committee (JTC) consists of employer and labour representatives and experts advisers. In the list of OELs, all substances listed by the ACGIH (USA) are included. Types of OELs are TWA, STEL and Ceiling. There are carcinogenity notations but no BEIs.

The OELs and their criteria are published in the Official Gazette. The OELs have legal force and they are often reviewed.


The OELs are reviewed through the OEL Task Force, including labor, management and ministry representatives. For the revision, criteria documents from other countries are used. Revised or new OELs are published in the Ontario Gazette. Some regulations for specific substances can be found on the Internet in the electronic "Gazette" under Occupational Health and Safety Act. A complete list of OELs is available only as paper version. The OELs have legal force.


The OELs are contained in the Chemical Hazards Regulation (Alberta Regulation 393/88). The Technical Committee of Occupational Exposure Limits, established by Alberta's Occupational Health and Safety, recommends and revises OELs. The committee consists of experts from the industry, academia, labour and government. The OELs and criteria documents are published in the Occupational Health and Safety magazine and legally binding.


In the Danish OSH system, the Grænseværdier for stoffer og materialer (limit values for substances and materials), are administrative instructions that are enforced under the Working Environment Act. The Ministry of Labour sets up the regulation on these limit values and the Arbejdstilsynet (Labour Inspectorate) publish the OEL list and supervise their execution. In the sphere of the Act, employers are obliged to keep the exposure as low as reasonably possible and the limit values should never be exceeded.

The Arbejdstilsynet decides on the OELs after consulting with employer and employee representatives on the technical and economical feasibility of the proposed limit value level. The scientific background is studied by the OEL setting committee acting under the Arbejdsmiljørådet (Council on Working Environment). This committee refers to the OEL criteria documentation provided by:

•The SCOEL (EU),
•MAK (Germany),
•DECOS (The Netherlands),
•the Nordic Expert Group (NEG), and the experience of the Inspectorate within the Danish workplaces. Usually, the committee gives a proposal for a limit value and a preferred safety factor (1, 2, 5, 10, 20...) for the substance.

In Denmark, most of the OEL values are TWA - 8h. For lead, there is also set a Biologisk eksponeringsværdi (biological exposure limit) for concentration in blood. An "H" ("Huden") in the tables annotates substances that can be taken into body via the skin. The allergic potential is not marked, but it is tentatively taken into account when setting the limit value level. For acutely toxic substances, like strong irritants, there is annotation L ("Loftværdi") on the limit value tables. The limit value for this substance must not be exceeded even for a short (less than 15 minutes) time. For acutely neurotoxic substances, the limit value should not be exceeded even for 5 minutes.

For specific hazardous substances, the Limit Values for Substances and Materials list the substances that are considered human carcinogens by the International Agency for Research on Cancer (IARC) or by the EU Commission. These substances are regulated by a specific order set by the Ministry of Labour. These substances are also annotated by "K" (kræftfremdkaldende, carcinogenic) on the OEL value tales. In addition, organic solvents are given a specific list of limit values, as they have to be particularly considered at workplaces.

Internet Links
The Labour Inspectorate (Arbejdstilsynet)


In Estonia, the occupational Exposure Limits are called Töökeskkonna keemiliste ohutegurite piirnormid. They are prepared and endorsed by the Ministry of Social Affairs, and are a part of the National Chemical Act regulations.

The limits are set with reference to current European Union and Swedish Occupational Exposure Limits. Social partners, OSH inspectors and representatives of the industry are given chance to comment on the proposed limit values. The table is revised when there are substantial changes in the corresponding EU legislation, or the are special problems with the chemical safety.

The Estonian table presents concentration limits for Time-weighted average (8 hour) and Short-term exposure limits (15 minute). There are also binding biological occupational limit values for lead in blood. Substances toxic for reproduction, carcinogenic substances, substances with sensitisation capabilities, and effective skin absorbents are annotated by R, C, S, and A, respectively.

Internet Links
The Ministry of Social Affairs, Estonia


The Finnish OEL system can be divided into legally enforcing binding limit values (sitovat raja-arvot) and more orientating concentrations known to be harmful (haitalliseksi tunnetut pitoisuudet, HTP -arvot). Both of these are connected to the Labour Protection Act, which oblige the employer to provide the employee healthy and safe working conditions. The Ministry of Social Affairs and Health publishes the OEL list in English, Swedish, and Finnish in paper form. The Finnish Institute of Occupational Health publishes the list in Finnish and English on its website.

The Ministry of Social Affairs and Health decides on Occupational Exposure Limits according to the proposal of the Advisory Committee for Occupational Health and Safety on Chemicals. The Council of State nominates the Advisory Committee for Occupational Health and Safety on Chemicals that operates under the Ministry of Social Affairs and Health. The Committee together with the Ministry's Occupational Safety and Health Department prepares the list of harmful concentrations. The Committee selects a Subcommittee of Exposure Limits, which does the actual preparatory work. The four subcommittee members represent:
•The Ministry,
•the chemical industry,
•employers' organisations, and
•the trade unions.

The subcommittee has three secretaries, who prepare documentation with a specific emphasis on the dose-effect relationships. The exposure limit is recommended after identifying the critical effect and reviewing the related literature.

All air limit values define two basic influence factors:
•The concentration - in mg/m3 or ppm, and
•the average exposure time in minutes or hours.

The exposure times are averaged for 15 minutes and eight hours, and some substances have momentary limit values, which should never be exceeded. The possibility of skin penetration is remarked by "Skin" (Iho). This annotation does not take into account the possibly corrosion or irritation potential of the substance. The potency to cause allergy may be considered when setting the OEL, but it is not annotated on the OEL list.

The Ministry has set a binding limit value for lead concentration in blood. Several other substances have also been set limit values for concentration in biological samples such as blood, urine, or alveolar air to amend the air limit values and help to measure the actual exposure in workplaces. In addition, the Finnish Institute of Occupational Health recommends reference limits for non-exposed and bio-monitoring action levels.

OELs are used in a number of other ways. For example:
•Guidelines on medical surveillance of workers are linked to occupational exposure limits. A certain fraction of the OEL exposure level can be a prerequisite for the need of periodical examinations.
•Defined fractions of occupational exposure limits are used to decide when special leave for pregnant workers is required when exposed to reprotoxic chemicals and their groups.
•Plant ventilation engineers also use OELs in their calculations.

Internet Links
OEL list published by the Finnish Institute of Occupational Health in English
The Ministry of Social Affairs and Health


In France, the Occupational (Air) Exposure Limits (OELs) are called "Valeurs limites d'exposition professionnelle aux agents chimiques en France" (VL). These VL are defined as the concentration of an agent in the air of the working area that a person can inhale for a defined duration without a risk of changes to his or her health. Furthermore, the VL should be seen as a minimum requirement. The VLs are fixed by the Ministère de l'Emploi et de la Solidarité (Ministry of Employment and Solidarity). Some values are also recommended by the National Illness Insurance Fund (CNAM). There are currently two types of OELs:
•Statutory and compulsory OELs for certain extremely hazardous substances; and
•recommended OELs for the remaining substances.

The Ministry of Social Affairs and Health decides on Occupational Exposure Limits according to the proposal of the Advisory Committee for Occupational Health and Safety on Chemicals. The Council of State nominates the Advisory Committee for Occupational Health and Safety on Chemicals that operates under the Ministry of Social Affairs and Health. The Committee together with the Ministry's Occupational Safety and Health Department prepares the list of harmful concentrations. The Committee selects a Subcommittee of Exposure Limits, which does the actual preparatory work. The four subcommittee members represent:
•The Ministry,
•the chemical industry,
•employers' organisations, and
•the trade unions.

Two types of OEL values exist in France:
•Short-term exposure limit values (valeurs limites d'exposition à court terme) are ceiling values for measured over one duration of maximum 15 minutes; and
• average exposure limit values (valeurs limites de moyenne d'exposition) are measured or estimated over the duration of 8 hours.

The OELs are established and revised by the Comité Scientifique pour la Surveillance des Atmosphères de Travail (Scientific Committee for Surveillance of the Workplace), working under the High Council for the Prevention of Occupational Hazards Environment. The committee is made up of experts, scientists and industrialists involved with chemicals. The OELs are based on the review on the international scientific literature and studies undertaken by the regional authorities in France. Then the technical and economical feasibility of the proposed health-based OEL is studied mostly by the industry participating in the limit setting and reviewing. After endorsement the OELs are published in the French Official Journal, Official Bulletin and in the publications of the Institut National de Recherche et de Sécurité, INRS (National Institute of Safety Research). The INRS publishes parts of the VL on the Internet.

Internet Links
The Ministry of Employment and Solidarity (Ministère de l'Emploi et de la Solidarité)


In Germany, there are two kinds of OELs for air in the workplace:
•TRKs (Technische Richtkonzentrationen), which ar e technical guidance concentrations, and
•MAKs (Maximale Arbeitsplatzkonzentrationen), which give the maximum concentration of a chemical substance in the workplace.

The MAK-values are daily 8-hour time-weighed average values and apply to healthy adults. Substance-specific acceptable peak concentrations, including the highest possible duration of such peaks, are defined. If the substance can be taken up through the skin, this is indicated.

The TRK is the concentration of a chemical substance in the air within a working area, which may be reached in accordance with the best available technology (state of the art). This type of limit value is usually applied to substances that are in carcinogenic category 1 or 2. In some cases, the Committee on Hazardous Substances proposes technical-based MAK-Values which base on the TRK-concept (TRGS 102). These type of limit value usually applies to substances which are carcinogenic or mutagenic category 3 (substances suspected of having a carcinogenic or mutagenic potential) and to important industrial substances for which no harmless minimum concentration can be determined (e.g. Cobalt, metal working fluids).

In addition to these, there are special rules for individual substances or substance groups such as hydrocarbon mixtures, diesel engine emissions, or different types of fibres and dust. The Biologische Arbeitsstofftoleranzwerte, or BAT, (Biological Tolerance Values) give limits for the concentration of some substances in the human body from workplace exposure.

The limit values for hazardous substances are documented in Technical Rules for Hazardous Substances (TRGS). The TRGS describe the substances with respect to the current status of knowledge about the health hazards, typical industrial use and safety and hygiene requirements. They are based on the Hazardous Substances Ordinance (GefStoffV) which is derived from the Chemicals Act (ChemG). All exposure limit values are consistent national values based on common national legislation. The Federal Ministry of Labour and Social Affairs publishes new or revised limit values half-yearly. The MAK and TRK values are published in TRGS 900 (Limit Values in the Air at the Workplace) and the BAT are covered in TRGS 903.

The Ausschuss für Gefahrstoffe (AGS), or Committee on Hazardous Substances establishes the Technical Rules. This Committee consists of members from all concerned groups. The authorities are represented by:
•Delegates of the labour inspections from the Länder (Federal States);
•Institutions for statutory accident insurance and prevention (BG, HVBG)
•National institutions such as:
oThe Hazardous Substances Division of the Federal Institute for Occupational Safety and Health (BAuA);
oThe Federal Environmental Agency (UBA);
oThe Federal Institute for Health Consumer Protection and Veterinary Medicine (BgVV); and oThe Federal Institute for Material Research and Testing (BAM).
oThe employers, the producers and sellers of chemicals, the trade unions and the consumers are also represented.

Limit values are developed and proposed by national scientific sources. For example:
•The DFG Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work area - the MAK Commission;
•The Committee on Hazardous Substances •Scientific departments of the chemical industry

International scientific proposals or official values from other States may also be included in the list.

For health based OELs of "threshold substances", recommendations of the MAK-Commission and other sources are discussed by the Beraterkreis Toxikologie (Advisory Group on Toxicology), of AGS, the Committee on Hazardous Substances. This Committee recommends a health-based OEL to the AGS, where in exceptional cases socio-economic and feasibility aspects may be taken into account. Thereafter the AGS recommends the OEL to the Ministry of Labour and Social Affairs who include it in the Technical Rules TRGS 900.

Internet Links
Technical Rules can be obtained from BAuA

Hong Kong

Hong Kong's Occupational Exposure Limits are based on the American Conference of Governmental Industrial Hygienists' list of Threshold Limit Values and also on standards.

The OELs are adopted by the Labour Department of Hong Kong, who have the authority to adjust them based upon new health hazard information. The exposure limits apply only to those workplace operations covered by the Factories and Industrial Undertakings legislation.

Internet Links
The Hong Kong University of Science and Technology provide some basic information on OELs
Safety & Environmental Protection Office of the Hong Kong University of Science and Technology
Hong Kong Labour Department


In Ireland, the Occupational (Air) Exposure Limits (OELs) are defined as the maximum permissible concentration of a chemical agent in the air at the workplace to which workers may be exposed in relation to an 8-hour or a 15-minute reference period. These limits are set out in Schedule 1 to 1999 Code of Practice for the Safety, Health and Welfare at Work (Chemicals Agents) Regulations, 1994 (S.I. No. 445 of 1994). The 1999 Code of practice can be obtained as a priced publication from the Health and Safety Authority (HSA).

The establishment of OELs in Ireland is based on the Safety, Health and Welfare at Work (Chemical Agents) Regulations, 1994 (S.I. No. 445 Of 1994).

Internet Links
Health and Safety Authority
Statutory Instrument 1994 No.445 can be obtained from the Health and Safety Authority


The general law on 'health and safety for workers' and several ensuing presidential decrees have achieved harmonisation to European Union legislation. Among the topics addressed in this legislation (e.g. occupational factors, working conditions) are provisions on enforceable occupational exposure limits for nearly 600 chemicals.

Most of the OELs reported are equivalent to the threshold limit values (TLV-TWA) published by the ACGIH (USA). The Italian exposure limits are identical with the TLVs established by the ACGIH (USA). The list exists as paper version. An updated list of the Italian laws concerning dangerous substances is available on the Internet at the URL of the National Institute of Occupational Safety and Prevention (ISPESL). The laws on the risks arising from exposure to chemical, physical and biological agents are also explained on the comprehensive ISPESL site, at

Internet Links


The Japanese Association of Industrial Health, a private academic organisation, recommends Permissible Exposure Limits (PELs). These OELs have no legal force. The majority of Japanese PEL-list values are the same as ACGIH (USA) Threshold Limit Values. The types of PELs are TWA, STEL, Ceilings and BEI (see under USA for an explanation of these terms). The OELs and their criteria documents are once a year published in the Japanese Journal of Industrial Health.

Internet Links
Japanese Journal of Occupational Health


The exposure limits in Luxembourg are adopted from various international health and safety agencies. The exposure limits in Luxembourg are based on the regulation of 19 July 1991. OELs used in Luxembourg are the same as used in Germany, unless specific OELs are provided.

The legislation can be found on the Internet on the web site of the Inspection du Travail et des Mines (Inspectorate for Labour and Mines) of the Ministère du Travail et de l'Emploi (Ministry of Labour and Employment).

Internet Links
Inspection du Travail et des Mines
Ministère du Travail et de l'Emploi


The Secretariat of Labor and Social Welfare (STPS) is responsible for setting standards regarding Permissible Exposure Limits (PEL). The list is based on the ACGIH (USA) Threshold Limit Values.

The scientific basis is the use of ACGIH criteria documents. The Secretariat of Commerce and Industrial Development (SECOFI) publishes the standards in the Official Journal of the Federation. The standards have legal force. The Diario Oficial de la Federación (Mexican Federal Official Journal) is available via website of the Secretaría de Economía.

Internet Links
Secretaría de Economía web site

New Zealand

In New Zealand, the Occupational Exposure Limits are called Workplace Exposure Standards (WES). These include Time Weighted Averages (TWAs), Short Term Exposure Limits (STELs) and Biological Exposure Indices (BEIs). The WESs are reviewed annually, and a list is published by the Occupational Safety and Health Service of the Department of Labour.

The exposure limits are prepared by an expert committee, consisting of representatives of the Occupational Safety and Health Service of the Department of Labour, toxicologists, and medical/scientific experts as required. The committee considers documentations from ACGIH (US), HSE (UK), NOHSC (Australia), and MAK (Germany).

The WESs are intended to be used as guidelines for those involved in occupational health when applying the hierarchy of control set out required by the Code of Practice for the Management of Substances Hazardous to Health and obliged under Health and Safety in Employment Act. An employer is required to take all practical steps to either prevent exposure to the hazardous substance or to reduce the exposure to the lowest practicable level.

Internet Links
The home page of the Occupational Safety and Health Service of the Department of Labour


Norway, the Arbejdstilsynet (Central Labour Inspectorate) issues OELs. The Inspection has established a working group with representatives from the employers, employees and direction of the inspection. As scientific base are used criteria documents from the Nordic Countries, Germany and United States and Norwegian workplace experience. There are values for TWA, STEL and Ceiling. There is also notation for issues such as carcinogenicity.


In Portugal, the occupational exposure limits for dangerous substances are published in the Portuguese Standard 1796 of 1988. The publisher is the Portuguese Institute of Quality. The Standard 1796 is currently being reviewed. The VLEs (OELs) reported in this Standard as well as in the new Standard are equivalent to the limit values published by ACGIH (USA). In the future Portuguese Standard should contain time-weighted average for 8hrs (TLV-TWA), ceiling values (TLV-C) and the short-term exposure limits (STEL).

Exposure limits have been legislated in the decree-law 274/89 for lead and its compounds (transposing Council Directive 82/605/EEC) and in the decree-law 273/89 for monomerous vinyl chloride (transposing Council Directive 78/610/EEC).

Internet Links
Portuguese Institute of Quality
Direcção de Serviços de Prevenção de Riscos Profissionais, Instituto de Desenvolvimento e Inspecção das Condições de Trabalho, Lisboa

South Africa

In the Republic of South Africa both the Department of Labour and the Department of Minerals and Energy issue Occupational Exposure Limits (OELs) for airborne pollutants.

The OELs from the Department of Labour are based on the OELs of the United Kingdom and described in the Hazardous Chemical Substances Regulations (Annexure 1) of 1995. The limit values are set by the Minister through the Chief Inspector on recommendation of an Advisory Council and listed by notice in the Government Gazette. Working with asbestos or lead is subject to special regulations.

Department of Labour Exposure Limits are divided in OEL-RL (recommended limit) and OEL CL (control limit), the latter relating to the very problematic substances such as carcinogens. They are listed in table 1 respectively table 2 of the said annexure.

An OEL-CL is defined as the maximum concentration of an airborne substance, averaged over a reference period, to which employees may be exposed by inhalation under any circumstances, and is specified together with the appropriate reference period in Table 1 of Annexure 1. Control measures are considered adequate if the air concentration is below the OEL-CL values.

An OEL-RL is defined as the concentration of an airborne substance, averaged over a reference period, at which, according to current knowledge, there is no evidence that it is likely to be injurious to employees if they are exposed by inhalation, day after day, to that concentration. It should be kept as much below the OEL-RL value as practicably possible.

In addition to the above limit values the Department of Labour sets Biological Exposure Indices (BEIs) to supplement the exposure monitoring.

The Hazardous Chemical Substances Regulations and the occupational exposure limits in this publication do not apply to exposure to substances hazardous to health in mines. The OELs from the Department of Minerals and Energy are described in the Occupational Hygiene Regulations of 2002, OELs for Airborne Pollutants Schedule 22.9(2)(a)

Internet Links
The OELs and the background legislation can be viewed under the following URL from the South Africa Institute of Occupational Hygiene
South Africa Institute of Occupational Hygiene (SAIOH)
South Africa Department of Labour
The Mine Health and Safety Act
South Africa Department of Minerals and Energy

The standards are recommendations and they are not legally binding until they are used by the labour inspection in orders or instructions for companies. The list is reviewed yearly.


The legal framework for limit values for hazardous substances (in Spanish: VLA = Valore Límite Ambientales) is under reconstruction. Beside the European Directive-based legislation, based for example on EC Directive 98/24/CE - the Chemical Agents Directive, two Spanish regulations exist. Since 1961, a national ordinance about health impairing and dangerous activities at work places is in force entitled Reglamento de Actividades Molestas, Insalubres, Nocivas y Peligrosas. This ordinance did not include single OELs. When OELs were needed in practice the ACGIH's (USA) limit values were used. Since 1998 the (Instituto Nacional de Seguridad e Higiene en el Trabajo, or INSHT (National Institute for Occupational Safety and Health) has published a guide including a list of more than 500 OELs and instructions for the use and application of these values.

The OELs published by INSHT are developed by a working group of the Comisión Nacional de Seguridad y Salud en el Trabajo (National Commission of Safety and Health at Work). Their work is based on the Spanish law about the prevention of risk at the work places from November 1995 and the Royal Decree 39/1997. All limit values for hazardous substances are recommendations. They become legally binding when they are used by the Labour Inspectorate or other authorities in orders or instructions for companies. The "Límites de exposición profesional para agentes químicos en España" (Current OELs) are published in Spanish on the Internet and on paper and are renewed yearly by the INSHT.

The limit values for air-concentrations of carcinogenic and mutagenic substances are published in different special regulations. The list of OELs includes remarks about the mutagenic, carcinogenic and genotoxic potential of a substance. Substances with possible skin penetration are marked with "v.d." (vía dérmica).

The INSHT defines three different types of TLVs:
•VLA-ED (Valor Límite Ambiental Exposición Diaria), the limit for the daily average concentration. For 30 minutes period, an employee's exposure can be three times the VLA-ED. The exposure should never exceed the level of five times the VLA-ED.
•VLA-EC (Valor Límite Ambiental Exposición de Corta Duración) is the limit for short-term exposure concentration. The VLA-EC should not be exceeded during any part of the working exposure. It may be used as an OEL for highest 15 minutes per day.
•VLB (Valor Límite Biológico) is a limit value for the content of the substance in biological media (i.e. blood, urine). VLBs have been defined for dozens of substances.

Internet Links
Ministerio de Trabajo y Asuntos Sociales
Occupational Exposure Limits 2003


The "Hygienic limit values and measures for air pollutants" (Hygieniska gränsvärden och åtgärder mot luftföronreningar, Arbetarskyddsstyrelsens författningssamling; AFS 2000: 3) is an instruction given by the Swedish Work Environment Authority (Arbetsmiljöverket) with the empowerment of the Work Environment Ordinance (Arbetsmiljöförordningen; SFS 1977: 1166). These regulations are based on the Work Environment Act (Arbetsmiljölagen; SFS 1977: 1160) and the limit values are a starting point of the chemical risk management.

According to the national regulations, the employer is obliged to keep the exposure level as far below the limit value as possible.

The scientific background documentation is prepared by the Kriterigruppen för hygieniska gränsvärde, Arbetslivsinstitutet (Criteria Group of the National Institute of Working Life). The Group drafts a consensus report after reviewing the scientific literature on toxicological grounds. These reports are published in the "Arbete och Hälsa" series. The Arbetarskydsstyrelsen (National Board of Occupational Safety and Health) proposes an OEL according to the consensus report for the Labour Market Parties. After the communication, the directorate of the National Board gives a new ordinance on Occupational Exposure Limit (OEL) Values. The Arbetsmiljöinspektionen (Work Environment Inspection) controls the execution of the OEL ordinance.

Most of the OELs are maximal values of air concentrations in workplace air. The concentration limits are averaged over certain time periods, which are generally eight hours ("maximal limit value", or nivågränsvärde) and 15 minutes ("short-term limit", kortidsvärde). The ceiling values (takgränsvärde) are momentary limit values and the reference time can be as short as 5 minutes. In the OEL lists, "K" (Cancerframkallande, Grupp C), annotates carcinogenic substances, "S" (Sensibiliserande, Grupp D), annotates sensitisers and "R" (Reproduktionsstörande, Grupp E), indicates substances toxic to reproduction. In addition, the "Hygienic limit values and measures for air pollutants" includes lists of substances, which are banned (Grupp A) or subject to license (Grupp B). Isocyanates, which are included on the OEL list, are regulated also by specific instructions on "Hard plastics" (Härdplaster; AFS 1996:4). H" ("Huden") annotates substances with the capability of skin penetration on the OEL lists. The allergic potential is considered when setting the limit value.

Biological monitoring can provide information on the exposure for many substances. For lead and cadmium, The Arbetarskydsstyrelsen has set exposure limit values, which oblige the employer. Regulations concerning these are defined in "Medical control on cadmium work" (Medicinsk kontroll vid kadmiumarbete; AFS 2000:7) and "Lead" (Bly - Ändrigen av AFS 1992:17; AFS 2000:13)

Internet Links
Swedish Pages of the European Agency Network
National Institute of Working Life (NIWL)


The Swiss list of exposure limits, with its MAK and BAT values, is modelled after the German MAK list (and somewhat after the ACGIH - American Conference of Governmental Industrial Hygienists – the TLV list).

Maximale Arbeitsplatzkonzentrationen (MAKs), or maximum workplace concentrations, give the maximum concentration of a chemical substance in the workplace. They are the maximum allowable average concentrations of a working substance in the air in form of gas, steam or dust, whereby it can be assumed that the health of the vast majority of healthy employees being exposed to these substances during an 8-hours working time up to 42 hours a week or even over longer periods will not be harmed.

Biologische Arbeitsplatztoleranzwerte (BATs) , Biological Tolerance Values, give limits for the concentration of some substances in the human body from workplace exposure.

The Swiss list contains substances that are considered harmful to humans, together with their applicable limit values. It also contains information and safety precautions for particular problem areas, such as carcinogens, dust, noise, heat, pressure, vibration, radioactive substances, and skin absorption, as well as remarks on testing methodology.

The limit values are documented in "Grenzwerte am Arbeitsplatz" (limit values at workplace) and are published by the Swiss National Insurance Fund (SUVA), in line with a decree of the Bundesrat and in conjunction with the limit value commission of the Swiss Association for Occupational Medicine, Hygiene and Safety.

Internet Links
The booklet "Grenzwerte am Arbeitsplatz" (besides German also available in French or Italian)


Occupational exposure limits in the UK function under the Control of Substances Hazardous to Health Regulations (COSHH) and its mirror legislation in Northern Ireland. The COSHH regulations require the employer to ensure that the employee's exposure to substances hazardous to health is either prevented or if not practically possible, adequately controlled. OELs in the UK can be divided in Maximum Exposure Limits (MELs) and Occupational Exposure Standards (OESs). Exposure should be reduced as far below an MEL as possible, while reduction to the substance specific level OES is considered adequate. The list of exposure limits is known as EH40 and is available from HSE Direct.

All legally enforceable OELs in UK are air limit values. The maximum admissible or accepted concentration varies from substance to substance according to its toxicity. There are some OELs for multi-substance exposure prescribing process emissions like welding fumes. Biological monitoring results may be used as indicators of exposure, although they have not got legal status. The Biological Monitoring Guidance Values (BMGV) are provided also in the HSE series EH40.

The exposure times are averaged for eight hours (8-hour TWA) and 15 minutes (short-term exposure limit STEL). For some substances, a brief exposure is considered so critical that they are set only a STEL, which should not be exceeded even for a shorter time. The potency to penetrate through skin is annotated in the OEL list by remark "Skin". Carcinogenicity, reproduction toxicity, and irritation and sensitation potential are considered when preparing a proposal for an OEL according to the present scientific knowledge. The OELs do not cover some hazardous substances that have their own specific legislation, most notably asbestos and lead.

Health and Safety Commission's Advisory Committee on Toxic Substances (ACTS) recommends new OELs or revision on a current OEL value. The Working Group on the Assessment of Toxic Chemicals (WATCH) is a technical sub-committee of ACTS, which considers the evidence on the occupational exposure and health effects of substances, including whether a MEL or OES would be appropriate by the agreed indicative criteria, and if an OES, its value. After the ACTS (constituting of representatives of employers, workers, government and environmental and consumer experts) has approved a MEL or OES it is endorsed by the Health and Safety Commission (HSC).

Internet Links
HSE Direct
UK Pages of the European Agency Network
The Health and Safety Executive
The LEV calculator
The LEV video
Designers, installers and examiners
Clearing the air (buyers and users guide)


The Occupational Safety systems in the United States vary from state to state. Here, Information is given on major providers of the Occupational Exposure Limits in the USA - ACGIH, OSHA, and NIOSH.


The American Conference of Governmental Industrial Hygienists (ACGIH) publishes since 1946 Maximum Allowable Concentrations (MAC), which were later renamed to "Threshold Limit Values" (TLVs). Threshold Limit Values are defined as an exposure limit "to which it is believed nearly all workers can be exposed day after day for a working lifetime without ill effect". The ACGIH is a professional organisation of occupational hygienists from universities or governmental institutions. Occupational hygienists from private industry can join as associate members since shortly.

Today, 9 ACGIH committees focus their energies on a range of topics such as agriculture safety and health, air sampling instruments, bio-aerosols, biological exposure indices, construction, industrial ventilation, infectious agents, chemical substance TLVs, and physical agent TLVs. Once a year, the different committees propose new threshold limits or best working practice guides. The list of TLVs includes more than 700 chemical substances and physical agents, as well as dozens of Biological Exposure Indices for selected chemicals. Substances are nominated by the TLV Committee based on new occupational exposure data or requests of governmental organisations, workers, industry etc.. The committee decides which substances selected for consideration are to be studied and votes at least once a year on action items.

The committee has developed selection criteria for substances, taking into account scientific evidence or workplace experience. Every TLV or BEI is developed and based on the available, relevant, scientific data for that agent. Some TLVs include also skin and carcinogenity notations and Biological Exposure Indices.

The ACGIH defines different TLV-Types as there are:
• Threshold Limit Value - Time-Weighted Average (TLV-TWA): the time-weighted average concentration for a conventional 8-hour workday and a 40-hour workweek, to which it is believed that nearly all workers may be repeatedly exposed, day after day, without adverse effect.
•Threshold Limit Value-Short - Term Exposure Limit (TLV-STEL): the concentration to which it is believed that workers can be exposed continuously for a short period of time without suffering from
•chronic or irreversible tissue damage, or •narcosis. STEL is defined as a 15-minute TWA exposure, which should not be exceeded at any time during a workday
•Threshold Limit Value - Ceiling (TLV-C): the concentration that should not be exceeded during any part of the working exposure.
•Excursion Limits. There is a general excursion limit recommendation that applies to those TLV-TWAs that do not have STELs. Excursions in worker exposure levels may exceed 3 times the TLV-TWA for no more than a total of 30 minutes during a workday, and under no circumstances should they exceed 5 times the TLV-TWA, provided that the TLV-TWA is not exceeded.

ACGIH-TLVs do not have a legal force in the USA, they are only recommendations. OSHA defines regulatory limits. However, ACGIH-TLVs and the criteria documents are a very common base for setting TLVs in the USA and in many other countries. ACGIH exposure limits are in many cases more protective than OSHA's. Many US companies use the current ACGIH levels or other internal and more protective limits.

Internet Links
Reference resource


The Occupational Safety and Health Administration (OSHA) of the U.S. Department of Labour (USDOL) publishes Permissible Exposure Limits (PEL). PELs are regulatory limits on the amount or concentration of a substance in the air, and they are enforceable. The initial set of limits from 1971 was based on the ACGIH TLVs. An attempt to extend the number of TLV to other widely used chemicals was proposed by OSHA in 1989. OSHA additionally proposed in 1992 to apply most of these new and revised limits to construction, maritime, and agriculture. OSHA currently has around 500 Permissible Exposure Limits (PELs) for various forms of approximately 300 chemical substances, many of which are widely used in industrial settings. Existing PELs are contained in a document called "29 CFR 1910.1000", the air contaminants standard.

If OSHA determines that a specific standard is needed, any of several advisory committees may be called upon to develop specific recommendations. There are two standing committees, and ad hoc committees may be appointed to examine special areas of concern to OSHA. All Advisory committees, standing or ad hoc, must have members representing management, labour, and state agencies, as well as one or more designees of the Secretary of Health and Human Services. The two standing advisory committees are:
•National Advisory Committee on Occupational Safety and Health (NACOSH), which advises, consults with, and makes recommendations to the Secretary of HHS and to the Secretary of Labor on matters regarding administration of the Act.
•Advisory Committee on Construction Safety and Health, which advises the Secretary of Labor on formul ation of construction safety and health standards and other regulations.

OSHA uses in a similar way as the ACGIH the following types of OELs: TWAs, Action Levels, Ceiling Limits, STELs, Excursion Limits and in some cases BEIs.


The National Institute for Occupational Safety and Health (NIOSH) has the statutory responsibility for recommending exposure levels that are protective to workers. NIOSH has identified Recommended Exposure Levels (RELs) for around 700 hazardous substances. These limits have no legal force. NIOSH recommends their limits via criteria documents to OSHA and other OEL setting institutions.

Types of RELs are TWA, STEL, Ceiling, Biological Exposure Indices. The recommendations and the criteria are published in several different document types, such as Current Intelligent Bulletins (CIB), Alerts, Special Hazard Reviews, Occupational Hazard Assessments and Technical Guidelines.

Other US OEL publishers
Other exposure limits exist in the USA, published by organisations including:
•The American Industrial Hygiene Association (AIHA);
•The MSHA (Mine Safety and Health Administration);
•The American National Standards Institute (ANSI);
•The U.S. Navy.

Internet Links
US-EU Cooperation on Workplace Safety & Health
Definitions of TLV terms
The TLVs and BEIs
Some downloadable TLV and BEI documents
For the ACGHIH (USA) Threshold Limit Value List
OSHA's limit Values and criteria documents
NIOSH's documents and lists