Finding out how much of a hazardous substance a worker is exposed to is called exposure monitoring. This could include hazardous substances such as welding fumes (metal fumes), respirable crystalline silica (RCS), wood dust, flour dusts, solvent vapours, chromic acid mists and numerous hazardous gases and vapours.

As part of the duties of an employer under the COSHH Regulations, there is a requirement to show adequate control of these substances which are known to be hazardous to health.

The most common method is to measure the airborne concentrations of one or more hazardous substance in operators’ breathing zones. The results can be compared with published limits to determine the degree of control and hence the level of risk.

Other forms of exposure monitoring may involve biological monitoring. This could include testing a workers urine (urinalysis), blood, breath or skin. They all can be a powerful tool in determining whether an operator has been exposed to a hazardous substance.

Some substances with more potent toxic effects have a further requirement to monitor on a more frequent basis, e.g. carcinogens such as hexavalent chromium, benzene and rubber fume and respiratory sensitizers such as wood dust, flour and isocyanates.

Newcastle Occupational Health and Hygiene Ltd have experience of monitoring personal exposures of a diverse range of airborne hazardous substances include dusts, mists, fumes, gases and vapours. Exposure to a substance can be carried out as part of a full investigative programme, or as part of a routine assessment in order to update COSHH records. Substances and processes include, among others:

• Solvent vapours associated with painting and printing
• Chemical vapours associated with electro-plating processes
• Chemical vapours associated with the manufacture of materials or substances
• Inhalable dusts associated with woodworking
• Inhalable dusts, fumes and gases associated with metalwork fabrication (welding)
• Flour dusts in bakeries
• Anaesthetic gases in operating theatres
• Oil mists from metal turning and processing
• Respirable crystalline silica dusts from the manufacture of quartz glass and masonry works

Exposure monitoring, background monitoring or biological monitoring of many other workplace substances can be also undertaken as part of an overall risk assessment.

In all cases, following the investigation, a comprehensive report is supplied, describing the monitoring program, presenting the results obtained, discussing the findings and recommending a full and comprehensive range of remedial actions where necessary.