Rosin, also known as colophony, is the sap that comes from pine and spruce trees. Rosin (colophony)-based solder flux fume is a substance released during the soldering process.
Hazardous substances in the work environment are subject to the Control of Substances Hazardous to Health Regulations 2002 as amended (COSHH). These regulations require that the exposure of employees to substances hazardous to health is prevented or, where this is not reasonably practicable, adequately controlled. Rosin-based solder flux fume has been classified as a substance that may cause asthma, and exposure must be controlled to at least below the workplace exposure limit (WEL).
The HSE fined a national company in Gloucestershire £100,000 plus £30,000 in costs when it failed to have adequate control measures to remove rosin-based fumes from a workshop area – the need for control, or to replace the rosin-based solder with a rosin-free alternative, having been identified in 1999 but not put in place until 2003.
First Environment was asked by a client to investigate the concentrations of rosin-based solder flux fume arising from the testing of wire components for soldering strength. The initial investigation found concentrations in air above the WEL. The material could not be replaced and the process was necessary for the client’s work, so First Environment worked with the client to find a solution. No local exhaust ventilation (LEV) had previously been used; with our help the client identified a suitable LEV system, and further monitoring after its installation showed results significantly below the WEL for rosin-based solder flux fume.
As contact with solder fumes and residues may cause skin problems such as contact dermatitis, gloves were recommended when the rosin-based liquid was being used. It was also recommended that potentially exposed employees undergo regular health surveillance and that regular monitoring be conducted.