Isocyanates-Are you at risk?

Recently Nelson-based panel beating and spray painting business L&L Marriott Holdings Limited has been fined $15,000 for breaching a WorkSafe prohibition notice.

On 14 March 2014 WorkSafe health and safety inspectors visited L & L Marriott Holdings Limited’s premises and saw spray painting in a workshop area with no extraction system. There were unsafe lights and electrical sources in the same area as the spray painting, creating a risk of explosion. The spray painter was wearing a half mask respirator, which is unsuitable for spray painting with isocyanates, and another employee was walking around the workshop area with no personal protective clothing or respiratory equipment on when paint fumes were clearly visible.

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Isocyanates are compounds containing one or more -N=C=O groups, which can combine with other compounds containing alcohol groups. The largest volume use of isocyanates is in the production of polyurethane foams.

Examples of work activities involving isocyanates which require special attention include:

• All stages of manufacture and use where free isocyanates are released as vapours, aerosols and mists;

• Spraypainting; and

• Processes where heat decomposition of polyurethane products occur, such as welding, heat removal of electrical insulating varnishes and hot-wire cutting of urethane foam.

Health surveillance should be extended to all processes where significant exposure to isocyanates in the form of vapour or aerosol may occur. This includes spray painters using isocyanate-based paint systems. It is the responsibility of the employer to arrange health surveillance of their employees annually that includes a survey, assessment of exposed workers for skin and respiratory symptoms and education about isocyanates and protecting their health.

Health effects may follow acute or chronic exposure to isocyanates. Isocyanates can cause respiratory sensitisation and lead to occupational asthma. Isocyanates splashes in the eyes can cause severe chemical conjunctivitis. Isocyanates are also mild skin irritants, and can cause dermatitis. Sensitisation of the skin may occur, but this is not common. 4,4-Di-isocyanate dicyclohexyl methane is an exception, being a potent skin sensitiser.

In sufficiently high concentrations in the air, isocyanates have a primary irritant effect on the respiratory tract. Sensitised workers may exhibit asthmatic symptoms when subsequently exposed to atmospheric concentrations well below the Workplace Exposure Standard. Exposure of sensitised workers may initiate reduction in respiratory capacity immediately on exposure, some hours later, or both. There is evidence that for sensitised workers, recurrent exposures may result in impairment of ventilator function and poor recovery.

Other health effects may include liver and kidney dysfunction.