Health & safety – solvent health hazards
Techniques for protecting operatives against hazards encountered in many factories.
Many industries still use organic solvents or preparations containing them in a range of products, including adhesives, primers, cleaners, degreasers, inks and finishing agents. Exposure to these solvents can have serious health effects on the human body. Factory managers and supervisors need to be aware of the hazards involved and know how to ensure workers are protected from them. While the health risk will partly depend upon the toxicity of a particular solvent, the way in which a product is handled is also critical. The results of human exposure to solvents have been assessed and recorded over many years, forming the basis of today’s recommended exposure limits. The specific legislation, which governs the maximum solvent exposure limits, will vary from country to country. In the UK, for example, the limits are set under Control of Substances Hazardous to Health (COSHH) regulations by the Health and Safety Executive (HSE), while limits in the USA are set by the Occupational Safety and Health Agency (OSHA) under Standard 29 CFR.
The three ways that solvents can enter the body are by inhalation, ingestion and skin absorption. Volatile solvents will rapidly form a vapour in air, which can be inhaled and then passed into the bloodstream through the lungs. Solvents may also be ingested when a worker touches food or cigarettes with contaminated fingers. The skin may also absorb solvents on contact and these will travel through the bloodstream, possibly affecting the whole body. Once inside the body, solvents can cause short-term effects or long-term problems after repeated exposure. The typical effects of a single short-term exposure can include headaches, drowsiness, poor co-ordination, nausea and dermatitis. In cases of exposure to high solvent levels, unconsciousness or even death may result. If the operative is exposed to repeated doses, in many cases – even at low levels – the brain and central nervous system, heart, liver, lungs, kidneys and the fertility of both men and women can be affected. With many solvents (especially cheaper or low grade products), there is the potential for contamination with other chemicals – for instance, benzene – which is a known carcinogen and often found in toluene and xylene.
Furthermore, there are also the added risks of fire or explosion where solvents are used and stored.
“The three ways that solvents can enter the body are by inhalation, ingestion and skin absorption”
The following measures can be used to control the use and release of solvents into the atmosphere and to protect the health of the workers:
- use Local Exhaust Ventilation to extract the solvent vapours close to the source
- use preparations containing low-toxicity solvents to replace those of high toxicity (or switch to solvent-free preparations)
- minimise the amount of solvent preparations at the workstation. Ideally, the quantity should not be more than that required for half a day’s work.
- close all solvent receptacles when not in use
- label all solvent containers with the contents and use safe handling procedures, such as pumps and or funnels when transferring liquids
- dispose of all solvent-soaked rags or materials in airtight sealed metal containers
- limit exposure time in areas of high-solvent vapour concentration (for example, dispensing rooms)
- rotate workers to other areas so that continued exposure of an individual operative is reduced as much as possible
- use appropriate respirators and other personal protective equipment (PPE) if solvents cannot be eliminated or reduced.
Provision of personal protective equipment (PPE)
Respirator protection should be used only as a temporary solution or in special circumstances, such as the clean up of spillages. Paper or textile masks (even with charcoal inserts to capture solvent vapours) are not appropriate, as they do not protect the worker sufficiently. This is because the inserts are quickly saturated with solvent, thereby allowing vapours into the lungs. Suitably-approved gloves (for example, CE-marked product in the EU) should always be used when handling solvents, together with face shields, aprons and footwear as appropriate and according to the circumstances.
“Respirator protection should be used only as a temporary solution or in special circumstances, such as the clean up of spillages”
Monitoring solvent levels
Regular checks on solvent vapour exposure levels in the workplace are recommended as a duty of care to employees. These assessments are best carried out using solvent vapour ‘badges’ (figure 1) to determine if workers are being exposed to solvent levels which could damage their health. Solvent vapour monitoring badges contain special discs of activated carbon that absorb solvent vapours from the atmosphere.
Each badge is worn by an individual operative and absorbs all solvent vapours to which the wearer is exposed during a full work period. The badge is then sealed, ready for analysis. Most workplaces do not have the analytical equipment required to determine the types and levels of solvents absorbed by the badges and rely on a laboratory such as SATRA to carry out this work and report the results.
The solvent monitoring results should be part of a recognised health and safety management system. This will allow the factory supervisor to plan, measure and review health and safety issues in the workplace, and therefore demonstrate good practice.
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