Construction hazardous substances: Solvents
Solvents, often known as VOCs (volatile organic compounds), are used to dissolve or dilute other substances and can be found in many construction products such as paints, paint strippers, thinners and glues. Potentially harmful solvents include dichloromethane (DCM), also known as methylene chloride, toluene, xylene, white spirit, acetone and ethyl acetate. Certain tasks, such as spraying, can produce very high exposures. This page tells you how to control these risks and why.
What you should know
Solvents can make you ill by:
- Breathing vapours - paints and other products give off solvent vapours as they are applied, dry or cure.
- Skin contact - some solvents can be absorbed through the skin. Repeated or prolonged skin contact with liquid solvents may cause burns or dermatitis.
- Eye contact - contact with liquid solvent and solvent vapour can cause irritation and inflammation.
- Ingestion - you can take solvents into your body on contaminated food, drink and cigarettes.
Different solvents can affect your health in different ways. High airborne concentrations of some solvents can cause unconsciousness and death. Exposure to lower levels of solvents can lead to short-term effects including irritation of the eyes, lungs and skin, headaches, nausea, dizziness or light-headedness. Some of these effects may also increase your risk of having an accident. There can also be long-term effects on your health from repeated exposure to particular solvents. These may include dermatitis and liver, kidney or neurological diseases. If you are unsure what solvent your product contains you should check the product label or ask your supplier for a safety data sheet.
What you must do
The Control of Substances Hazardous to Health (COSHH) Regulations say you must protect against the risks from hazardous solvents. Follow the Assess, Control and Review model. Pay particular attention to:
Identify and assess: Identify tasks where potentially harmful solvent containing products will be used. Consider whether it is possible to eliminate the use of solvent by using an alternative method or solvent-free product, such as water-based paint. Consider:
- Who - think about your employees. Who is using products containing solvents, particularly organic types? Is anyone else likely to be around who might be affected by the work you are doing?
- What - which product are you using? What solvents are in it and how much? The higher the solvent content, the greater the risk. The risk is also greater for solvents that are more toxic, and those that produce more vapour. - Be aware that many solvents can produce a lot of vapour even at room temperature. Consider the overall effect if there is more than one solvent involved. This may be additive or, in some cases, greater than the sum of the individual effects. Look at the packaging and safety data sheet. Are there any other substances hazardous to health like isocyanates overview in the product..
- How - think about how you will do the work, how long it will take and the volume of solvents you are using. For example, there can be a big difference in exposure between painting using a brush compared to using a spray gun. Spraying will put more solvents into the air and use more paint in a shorter time.
- Where - the more enclosed the space, the greater the risk may be. - Lack of adequate ventilation can lead to the build-up of solvent in the air which may create a significant inhalation risk to workers and can be fatal. - General natural ventilation may not be sufficient for more hazardous tasks, so mechanical ventilation or extraction (LEV - local exhaust ventilation) may also be required.
Use this information to assess the level of risk. You are generally at lower risk if you are applying low solvent products with a brush / roller in a well-ventilated space. In contrast, spraying can be higher risk, particularly if working in an enclosed space with high concentrations of solvents and little air movement. Seek specialist help if you are unsure.
Where the risks are judged to be low, simple and inexpensive controls will suffice. For other tasks, like spraying, you may have to do more. The range of solvent containing products and the tasks you can use these for mean that you must decide on the specific controls you need based upon your assessment of the risks. Seek specialist help if you unsure about this. Give priority to the greatest risks first.
Reduce harmful emissions: Think about eliminating or reducing solvent risks where possible. Consider:
- using products containing little or no organic solvents such as 'water' based paints
- avoiding products containing more harmful solvents such as those classed as sensitisers
- whether you need to spray products with significant solvent levels. This causes more solvent to get into the air than using a brush or roller
- preventing unnecessary solvent evaporation by using the minimum amount for the job - keep lids on containers and use sealed containers for solvent -contaminated waste. Do not leave solvent-contaminated rags lying around
- do not use solvents to remove paint, grease etc from your skin
Control exposure: Even if you minimise some of the risk this way, you may still need to control solvent risks. Control this by using the appropriate measures below, and ensure that these measures remain in place during use of the product and until any mist or vapour has cleared:
- Segregation - keep all non-essential people away from the work area until the risk has been minimised.
- Ventilation - ventilation is always required. - For lower risk products it may be sufficient to make sure there is enough fresh air in the work area. Open doors and windows. The higher the risk the more ventilation will be needed. - DCM based products should only be used where there is effective ventilation and in most circumstances mechanical ventilation will be required.
- Respiratory Protective Equipment (RPE) - you may need RPE where ventilation does not provide enough control. The type of RPE depends on the product(s) and work methods you are using. For respirators, it is particularly important to select the correct filter and ensure wearers are fit tested. For example, particulate filters provide protection against spray mist but do not protect you from solvent vapours. You will need the right gas/vapour filter for these. Change them at suitable intervals. Check with your supplier if you're not sure. For DCM, other than for very short duration tasks where AX filters may be adequate, you will normally need constant flow airline breathing apparatus (CFABA). This is because DCM vapour can penetrate through respirator filters very quickly.
- Eye protection - wear eye protection (such as goggles or a face shield) when doing work where splashes / aerosol may get into the eyes. This must be compatible with any RPE.
- Gloves - gloves should be right for the products you are using For many organic solvents, single use nitrile gloves may be suitable for some tasks. For some solvents such as DCM, single use nitrile gloves will not be suitable and you should check the suitability with your supplier . Make sure the breakthrough time and permeation rate are right for the type and length of the work. You may need gauntlet style gloves to prevent skin exposure.
- Overalls - disposable overalls are preferred. Launder significantly contaminated re-usable overalls before wearing them again. It may be necessary to air them in a safe place first, to let the solvent evaporate.
- Washing - good washing facilities are essential. Wash off any product on the skin as soon as possible. Encourage people to wash exposed skin at breaks and after finishing work. Skin care products can also help replace the natural oils that help keep the skin's protective barrier working properly.
- First aid - give adequate and appropriate first aid Microsite treatment to anyone affected by solvents. You may also need to seek further medical attention.
Train: Workers need to know whether the products they are using contain solvents, and how to use the controls properly. They also need to be aware of the signs and symptoms of ill-health from solvent exposure.
Using paint stripper containing DCM at work is prohibited unless the worker is a competent person who has completed and passed the HSE competence training scheme and is certified. Before purchasing and/or using a DCM-based paint stripper, workers must attend a mandatory training course. Further information is available on HSE’s DCM Competency Training Scheme webpage.
Supervise: Ensure that controls, like ventilation, RPE and welfare, are used by the workers.
Monitor: You may need to check the effectiveness of your controls. This might mean:
- Health surveillance - you need to do this if there is a reasonable likelihood of getting dermatitis from your work. It could be done by a 'responsible person'. This can often be an employee with suitable training. They should :
- assess the condition of a new worker's skin before, or as soon as possible after, they start work and then periodically check for early signs of skin disease after this
- keep secure health records of these checks
- tell the employer the outcome of these checks and any action needed
- Exposure monitoring - there are different ways of monitoring exposure depending on the work and solvents you are using. Before you start, you should be clear about why you are doing exposure monitoring, what you are going to measure and how you will use the information.