Maximum workplace concentrations
In general, the primary aim of defining maximum workplace concentrations is to protect workers’ health, based on scientifically sound evidence.
In Germany, MAK (‘Maximale Arbeitsplatzkonzentration’: maximum workplace concentration) values are derived by the DFG Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, better known as the MAK Commission. This independent body has been mandated by the German Research Foundation (DFG) to determine the current state of research relating to the health risks posed by substances and materials used in the workplace, and to advise public authorities accordingly. The most important practical results of the Commission’s work are scientific recommendations for the establishment of MAK values and BAT values (biological tolerance values for occupational exposure), for the classification of carcinogenic, embryotoxic/fetotoxic substances and germ cell mutagens, and for the evaluation of measurement methods. The recommendations are freely available online (see Further reading).
|High water solubility, e.g. ammonia, sulfur dioxide, hydrogen chloride|
|Moderate water solubility, e.g. chlorine, hydrogen sulfide|
|Low water solubility, e.g. ozone, nitrogen dioxide, phosgene|
|Organic acids, e.g. acetic acid|
|Aldehydes, e.g. formaldehyde, acrolein|
|Amines. e.g. hydrazine, chloramines|
|Tear (CS) gas, mustard gas|
|Organic solvents, including some leather sprays|
|Some agrochemicals (paraquat, cholinesterase inhibitors)|
|Metallic oxides, e.g. those of cadmium, vanadium, manganese, osmium|
|Halides, e.g. zinc chloride, titanium tetrachloride, antimony pentachloride, uranium hexafluoride|
|Hydrides of boron, lithium, arsenic, antimony|
|Smoke from fires|
|Pyrolysis products from plastics|
|Spores and toxins from microorganisms|
Table 1 – Causes of chemical pneumonitis.
At the European level, the European Commission has set up the Scientific Committee on Occupational Exposure Limit Values (SCOEL), with a mandate to advise the Commission on occupational exposure limits for chemicals in the workplace. It does this by preparing scientific recommendations for the Commission, which are used to underpin regulatory proposals on occupational exposure limit values (OELVs) for chemicals in the workplace. During this procedure, draft recommendations from SCOEL undergo a stakeholder consultation to allow interested parties to submit health-based scientific comments and further data.
|Healthcare workers||Other occupations|
|Measles||Physicians and nurses|
|Mumps||Paediatricians and dentists|
|Parvovirus B19 infection||Nurses|
|Adenovirus infection||Staff in ophthalmology clinics,
intensive care units and longterm
|Influenza||Physicians and nurses||Office workers|
|SARS-coronavirus A||Physicians, nurses, healthcare
assistants and others; nursing
home attendants; housekeeping
personnel, laboratory workers
|Transport workers, business
travellers, market for exotic
|Avian influenza H5N1||Physicians, nurses, healthcare
|Poultry, farm and market
|Tuberculosis||Nurses, physicians, pathologists,
laboratory workers, housekeeping
|Anthrax||Hospital supply||Agricultural workers, wool
sorters, mail sorters
|HIV infection||Physicians, nurses, dental
workers and dentists, laboratory
workers, technicians in dialysis
unit, respiratory therapists
|Embalmers or mortuary
Table 2 – Respiratory infections that may be occupationally acquired. RSV: respiratory syncyntial virus; SARS: severe acute respiratory syndrome. Reproduced from Ho et al ., 2007, with permission from the publisher.
Recommendations adopted by the SCOEL are also available online (see Further reading).
In the USA, threshold limit values (TLVs) and biological exposure indices (BEIs), as defined by the American Conference of Governmental Industrial Hygienists, are determinations made by a voluntary body of independent knowledgeable individuals. They represent the opinion of the scientific community, after reviewing the available data, that exposure at or below the level of the TLV or BEI does not create an unreasonable risk of disease or injury (see www.acgih.org/TLV/ ).
|Acarians (ticks, mites)|
|Crustacea, seafood, fish|
|Plant-derived natural products|
|Aliphatic amines (ethyleamines and others)|
|Wood dust or bark|
Table 3 – Causes of occupational asthma.
|Man-made vitreous fibres|
|Environmental tobacco smoke|