Dust Hazards and the Control of Fumes

The exposure of employees to airborne dust or fumes can result in severe respiratory illnesses, such as occupational asthma. Such diseases can be totally disabling for the sufferer, causing them to give up work or at least change their employment.

Exposure of the skin to some hazardous dusts can result in severe irritation and ulceration of the affected areas.

Key points

  • The inhalation of dust or fumes has the potential to cause severe respiratory illness.
  • Asbestos fibres and lead dust are particularly hazardous if inhaled.
  • The dust of some types of wood can also be irritating to the skin.
  • Ideally, the creation of airborne dust or fumes will be prevented although that is often not possible in a construction site environment.
  • Where the prevention of dust or fumes is not possible, the extent of exposure must be controlled to a level that is acceptable.
  • Control is often achieved by the:
    – extraction of dust and fumes through stand-alone extractor-units;
    – collection of dust in ‘collector bags’ attached to powered hand tools;
    – wet cutting of solid materials such as thermal blocks, bricks or ceramic tiles.
  • Hazardous fumes usually result from:
    – processes in which materials are heated, such as welding, lead burning or grinding;
    – uncontrolled use of substances such as solvents and adhesives;
    – the use of equipment and plant powered by internal combustion engines.

Dust

It is widely known that almost any excess levels of dust can cause health problems. Harmful effects range from simple skin irritation to
severe respiratory illness. As well as visible dust which can be seen in the air, dusts that are too fine to be seen by the naked eye are also the cause of many serious health problems. It may take years for symptoms of ill health to manifest themselves.

Skin irritation, dermatitis and ulceration can be caused by contact with some dusts. Other types of dust, being soluble, may be absorbed
through the skin via cuts and abrasions.

The inhalation of dust can cause wheezing, coughing, breathlessness, bronchitis, and nasal and other types of cancer.

Stomach disorders may be brought on by the ingestion of dust, due to eating food with dirty and contaminated hands, or by working in a
very dusty area.

Such problems are not likely to arise if occupational exposure limits and the COSHH Regulations are observed and safe systems of
work maintained.

Fumes

Hazardous fumes can be produced when any one of many materials is heated or otherwise worked. A common form of respiratory illness,
which has flu-like symptoms, is caused by the inhalation of welding fumes.

Other sources of hazardous fumes are:

  • uncontrolled exposure to (generally) liquid substances such as solvents or paints.
  • the use of equipment and plant which is powered by internal combustion engines.

Legislative requirements

The Health and Safety at Work etc. Act 1974

The relevant provisions are as follows:

  • Employers must provide and maintain plant and systems of work that are safe and without risks to health.
    Reference :
    The Health and Safety at Work etc. Act 1974, Section 2(2)(a)
  • Employers must make arrangements for safe handling, storage, and transport of articles and substances.
    Reference:
    The Health and Safety at Work etc. Act 1974, Section 2(2)(b)
  • Employers must provide adequate information, instruction, training and supervision.
    Reference:
    The Health and Safety at Work etc. Act 1974, Section 2(2)(c)
  • Employers have a duty to ensure persons not in their employment are not exposed to risks to their health and safety.
    Reference:
    The Health and Safety at Work etc. Act 1974, Section 3
  • Persons in control of premises must use the best practicable means to ensure noxious or offensive substances do not enter the atmosphere.
    Reference:
    The Health and Safety at Work etc. Act 1974, Section 5

Note: Provisions relating to the emission of substances are also contained in the Control of Pollution Act 1974 and the Environmental Protection Act 1990.

  • Employers may not charge an employee for any personal protective equipment provided in accordance with statutory
    requirements relating to health and safety.
    Reference:
    The Health and Safety at Work etc. Act 1974, Section 9

Employees have a duty to:

  • exercise reasonable care for their own health and safety and that of others who may be affected by their acts or omissions; to co-operate with their employer in enabling him or her to carry out his or her duties under the relevant statutory provisions
    Reference:
    The Health and Safety at Work etc. Act 1974, Section 7
  • not intentionally or recklessly interfere with or misuse anything provided in the interests of health, safety and welfare.
    Reference:
    The Health and Safety at Work etc. Act 1974, Section 8

The Management of Health and Safety at Work Regulations 1999 (as amended)

These regulations place a legal duty on every employer to make a suitable and sufficient assessment of every work activity to identify any hazard that employees or any other person might encounter as a result of the work being carried out.

Once those hazards have been identified, it is then the employer’s duty to put control measures into place to either eliminate the hazards or, where this is not possible, reduce the risk of injury or ill health resulting from those hazards, so far as is reasonably practicable.

Where a hazard is identified that requires it, the employer must offer appropriate health surveillance to employees, taking into account the risks to their health and safety that have been identified.

The employer must provide employees with comprehensible and relevant information on any risks that exist in the workplace and inform them of any control measures that are in place to reduce those risks.

Employees, in turn, have a duty under these regulations to tell their employer of any work situation which presents a risk to the health and
safety of themselves to any other person who may be affected.

In the context of this module, these regulations require that employers assess the health risks to their employees arising out of exposure to hazardous dusts and fumes, and, if reasonably practicable, put control measures in place to eliminate the work processes and the use of substances that cause exposure. If that is not reasonably practicable, employers must:

  • control exposure to an acceptable level, and
  • inform employees of the hazards involved and the control measures employed
  • mitigate the effects of any exposure by providing health surveillance where necessary.

The Control of Substances Hazardous to Health Regulations 2002 (COSHH) (as amended)

Any concentration of any inhalable dust in excess of 10 milligrams of dust per cubic metre of air (10 mg/m3) averaged out over eight hours, or any respirable dust in excess of 4 mg/m3 averaged over eight hours is deemed to be a substantial concentration of dust and therefore within the definition of a substance hazardous to health.

Total inhalable dust approximates to the fraction of airborne material that enters the nose and mouth during breathing and is available for deposition in the respiratory tract.

Respirable dust approximates to the fraction that penetrates to the gas exchange region of the lung (the alveoli).
In addition, many types of dust are listed in the HSE Guidance Note EH40 and have specified workplace exposure limits (WEL). They are therefore classified as substances hazardous to health.

These regulations, in respect of any substance hazardous to health, must be complied with.
The principal points of the regulations place requirements on the employer to protect employees, or any other persons who may be affected by their operations, by:

  • assessing the health risks created by work involving substances hazardous to health. It should be noted that this is the same assessment as required under The Management of Health and Safety at Work Regulations 1999 (as amended).
    There is no need to carry out two assessments providing the requirements of both sets of regulations are complied with
    Reference :
    The Control of Substances Hazardous to Health Regulations 2002, Regulation 6
  • ensuring that the exposure of employees or others is prevented or adequately controlled, by putting in place any measures necessary to control the exposure to risks
    Reference:
    The Control of Substances Hazardous to Health Regulations 2002, Regulation 7
  • ensuring that any control methods provided are properly used and maintained, and by monitoring the work environment as necessary
    Reference:
    The Control of Substances Hazardous to Health Regulations 2002, Regulation 9
  • carrying out health surveillance in specified circumstances
    Reference:
    The Control of Substances Hazardous to Health Regulations 2002, Regulation 11
  • providing information, instruction and training for employees on the risks to health and precautions to be taken regarding any work with substances hazardous to health.
    Reference:
    The Control of Substances Hazardous to Health Regulations 2002, Regulation 12
  • providing procedures for dealing with accidents, incidents and emergencies, including first-aid and safety drills.
    Reference:
    The Control of Substances Hazardous to Health Regulation 2002, Regulation 13 Employers have no duty under Regulation 11 (health surveillance) to persons who are not their employees and no duty under Regulations 10 (monitoring), 12 (the provision of information and training etc.) and 13 (dealing with accidents) to persons who are not their employees unless they are on the premises where the work is being carried out.

Note: Further detail will be found in the Approved Code of Practice accompanying the COSHH Regulations.

The Personal Protective Equipment at Work Regulations 1992 (as amended)

These regulations require that where a risk has been identified by a risk assessment and it cannot be adequately controlled by other means which are equally or more effective, then the employer must provide and ensure that suitable personal protective equipment is used by the at-risk employees.

In essence, personal protective equipment (PPE) may only be used as a last resort after all other means of eliminating or controlling the risk have been considered and are found not to be reasonably practicable.
Reference:
The Control of Substances Hazardous to Health Regulations 2002, Regulation 7(3)(c)

In deciding which type to issue, the employer must take into account the nature of the hazard that the PPE is being used to protect against, and ensure the PPE will fit the wearer and allow them to work safely. If more than one item of PPE is being used, the employer must make sure that individual items of PPE are compatible and suitable for the task that is to be undertaken.

Whenever PPE is to be issued, the employer must ensure that employees have been given adequate and appropriate information, instruction and training to enable the employees to understand the risks being protected against, the purpose of the PPE and manner in which it is to be used.

Whilst the employer must ensure that personal protective equipment is supplied and used, the employee has a duty to properly use the equipment provided, follow the information, instruction and training that they have been given, and know the procedures for reporting loss or defect to their employer.

Training

It should be noted that all three sets of regulations place a legal duty on the employer to provide employees with adequate information, instruction, training and supervision to be able to carry out any work task safely and without risks to their health.

Respiratory hazards

The following paragraphs describe the main respiratory hazards which may be encountered on site.
Dusts are produced when solid materials are broken down into finer particles. The longer that the dust stays in the air then the easier it is to
breathe in. Airborne dust is usually respirable dust.

Mists are tiny liquid droplets formed by atomisation of the liquid, for example, when spraying or using an aerosol. Mists may be a combination of several hazardous substances.

Metal fumes occur when metal is vaporised at high temperatures, for example, when welding and gas cutting. As well as the fumes being a potential hazard to health, the vapour cools quickly and fine dust particles remain in the air.

Gases are airborne at room temperature and normally mix with the air that we breathe. Examples include propane, butane, acetylene, carbon monoxide and hydrogen sulphide.

Gases can spread very quickly. Vapours are the gaseous state of substances that are liquids or solids at room temperature. They usually form when substances evaporate.

One example is the vapour from a tin of glue or solvent that has been left open.

Exposure limits

Exposure to any unlisted substance or general nuisance dust should be limited by reducing dust levels to the minimum reasonably practicable. These levels should not exceed 10 milligrams of dust per cubic metre of air, when measured over an eight hour period (10 mg/m³ 8H TWA). Within that figure, only 4 mg/m³ should be respirable dust.

Generally speaking, if visible dust can be seen in the air, it is highly possible that the 10 mg limit is being approached (or possibly exceeded), and the application of the COSHH Regulations should be considered.

Dust

Dust in its many forms has been causing health problems throughout the history of the building and construction industry. While much attention has been given to newly recognised hazards, the greater part of the dust problem relates to more common substances.
Dust is taken here to mean anything that forms a powder or cloud and is a nuisance, including cement, wood, stone, silica, fillers and plastics.

The high speed cutting and grinding of most materials can produce dust. Dust in confined spaces is a special hazard, because of the known risk to health and the potential risk of explosion.

If dust is visible in the air then consideration will have to be given to the application of The Control of Substances Hazardous to Health Regulations 2002 (as amended).

In all cases, knowledge of the hazards associated with materials, processes and operations is required, and of the specific precautions and protective equipment necessary to reduce or eliminate the risk to health and safety.

Wood dust

Impregnated timber and some hardwoods (such as teak, African mahogany and iroko) are known to be health hazards. The inhalation of hardwood dusts through the nose is a known cause of nasal cancer.
A list of some timbers known to present risks is given below. Protection is not normally required when working on these timbers with hand tools in the open, but harmful dusts can be produced when using machine tools (e.g. sanders or saws) in enclosed or poorly ventilated areas.

An assessment under The Control of Substances Hazardous to Health Regulations 2002 (as amended) should be made and, if ventilation or dust extraction cannot be improved to remove or reduce the dust problem, a dust respirator should be worn.

Selection of timbers and their irritant effects

The severity and frequency of any symptoms will vary with individuals, and these are also dose-related.

Camphor wood – asthma, dermatitis Red cedar – asthma, bronchial trouble, sneezing, watering of eyes, dermatitis, septic wounds from splinters

Dahoma – irritation of mucous membranes and chest, sneezing, coughing, running eyes and nose, dermatitis

Ebony – irritation of nose and throat, dermatitis

Guarea (also West African cedar) – mild nasal irritation, sneezing, coughing, running eyes; can cause severe vomiting, chest irritation, blisters around the eyes and dermatitis

Iroko – skin and eye irritation, asthma and symptoms of the common cold

Machaerium – dermatitis

Sapele – dermatitis, allergic extrinsic alveolitis

Mahogany – asthma, dermatitis

Chestnut – asthma, dermatitis, rhinitis

Mansonia – irritation of mucous membranes, sneezing, nasal haemorrhage, eyes sore and bloodshot, dizziness, dermatitis

Satinwood – dermatitis, headache, coughing

Teak – dermatitis, eye inflammation. Effects are severe once the skin’s protective layer has been penetrated

Walnut – asthma, dermatitis, conjunctivitis, rhinitis

Yew – bronchial asthma and dermatitis

Generally speaking, the greater the amount and the finer the dust, the greater the risk of health problems.

Other common sources of dust

When cleaning stone, brick and concrete facades, or any metal structure with dry or wet grit blasting, employees must wear approved positive pressure respirators or helmets with a clean air supply, together with protective clothing, including goggles. When cleaning siliceous masonry, an air line helmet with an in-line filter is recommended.

Although this type of cleaning operation is commonly called ‘sand blasting’, sand must not be used for blast cleaning because of the known health hazard caused by airborne sand and silica.

Effective preventative measures must be taken if exposure to crystalline silica is possible.

Protection is also necessary when using mechanical cleaning methods.

Exhaust ventilation devices should be fitted to power tools, or the operative should be provided with high efficiency breathing apparatus.

The cutting and chasing of masonry, stone, brickwork, plaster, thermal insulating blocks and concrete creates a dust hazard. Therefore, extraction equipment should be provided, the process performed wet or respirators worn, depending on the assessment made under the COSHH Regulations.

The Health and Safety Commission has proposed that the workplace exposure level (WEL) to crystalline silica be reduced to 0.1 mgm3 due to concerns about the severe lung disease, silicosis, and a form of cancer that can occur as a result of inhaling this substance.

Crystalline silica (also known as quartz) is present in sand and rock and can also be found in building materials such as cement, concrete, plaster, bricks and tiles.
Dust from plastic fillers can damage the lungs if inhaled, as can dust from resin-based fillers, and fibrous particles of glass fibre, rockwool and similar insulation materials.

The dry sanding of lead-based paint can result in exposure to hazardous levels of lead dust.

The disturbance of asbestos is likely to result in the release of airborne fibres (dust) which can result in cancer and other respiratory illnesses if inhaled.

Where a work activity involves the creation or disturbance of dust, a COSHH assessment must be carried out.

Precautions

By providing the necessary facilities and equipment, following the procedures specified in the COSHH Regulations and complying with
the requirements of The Management of Health and Safety at Work Regulations 1999 (as amended), the risks can be greatly reduced.

The following points are especially important:

  • the identification of potentially hazardous work processes, materials and substances before work starts
  • the provision of information, instruction and training to employees
  • the strict observance of all recommendations and procedures advised by the manufacturer
  • the effective supervision of employees, and the monitoring of work methods and practices
  • the provision of protective clothing and equipment before any work starts
  • the correct disposal of waste materials and containers as recommended by manufacturers
  • cleaning by, for example, extracting dust using a vacuum cleaner, rather than stirring it up by sweeping
  • personal hygiene, including the cleansing of hands before consuming food, the use of barrier creams, the removal and storage of contaminated clothing during meals, and the correct laundering or disposal of contaminated clothing.

Protective equipment

As outlined earlier in this module, there are requirements under The Personal Protective Equipment at Work Regulations 1992 (as amended) which should be met when deciding upon the correct type of PPE to be used.

Given the nature of some work activities carried out, it is not always practical to completely contain the airborne dust or fumes created. In these circumstances, if no other control measure is reasonably practicable, respiratory protective equipment (RPE) and other PPE as necessary, must be provided for each person working with, or otherwise exposed to airborne dust or fumes.

There are various types of respiratory protective equipment approved for use. Details of types and permissible uses are available
from manufacturers.

Respiratory protective equipment

Selection

Selecting the wrong type of RPE could have serious, even fatal, consequences, therefore selection must be carried out by a competent person. Some of the factors that will determine the appropriate type of RPE are:

  • the hazardous nature of the substance
  • the airborne concentration of the substance
  • the period of exposure
  • the wearer’s required field of vision
  • the provision for communication
  • the need to move in cramped or difficult working places
  • the prevailing weather conditions
  • the suitability of the protective equipment for the individual
  • the need for an external source of breathable air.

Notes:

  1. When selecting suitable respiratory protective equipment (RPE) it may be necessary to seek expert advice from
    manufacturers/suppliers.
  2. Training in the types of, and in the use of, respiratory equipment must be given.
  3. Guidance and recommendations are provided in HSE publication: Respiratory protective equipment at work – A practical guide.

The following are some types of respiratory protective equipment (RPE) that are used in industry:

  • disposable face mask respirators
  • half-mask dust respirators
  • positive pressure powered respirators (standard and high efficiency)
  • high efficiency dust respirators
  • ventilated visor and ventilated helmet respirators
  • compressed air line breathing apparatus
  • self-contained breathing apparatus.

Note: Disposable face mask respirators and dust respirators are suitable only for protection against dusts. They will not protect the wearer against hazardous fumes.
The level of protection afforded by RPE also depends on the type of filter used. For example, a filter marked:

P1 – is a low efficiency filter offering a protection factor of 4

P2 – is a medium efficiency filter offering a protection factor of 10

P3 – is a high efficiency filter offering a protection factor of 20 if used on a half-mask respirator, or 40 if used on a full-face respirator.

A protection factor of 10 means that in controlled conditions the dust level inside the mask is 1 when the dust outside the mask is 10, or it is 2 inside the mask when outside it is 20, and so on. It is important, therefore, that the correct filter is selected for the level of dust in the air.

If there is any doubt regarding what level of protection is required, which type of respiratory protective equipment should be provided, which cartridge should be used on a respirator, etc. then advice should be sought from a competent person, or advice taken from the manufacturers or suppliers of respiratory protective equipment.

Disposable face mask respirators

These are simple face masks designed to filter out harmful dust and particles. They are lightweight, comfortable and cheap. They should only be worn by one person and for no longer than a single eight-hour shift. They should be disposed of after use.

In areas of high dust levels, it may be necessary to dispose of dust masks more frequently, since they may become clogged and, subsequently, breathing will become more difficult.

Disposable face masks are not generally approved for use to protect against asbestos, lead alkyls or other volatile organic compounds of lead, lead dust, welding fumes, or in metal foundries or casting shops.

In addition, they may not be suitable for protection against some specific dusts such as glass fibre, hardwood or silica.

Nuisance dust masks

Nuisance dust masks may comprise a metal plate that holds a piece of gauze over the nose and mouth. Alternatively, they may consist of a lightweight cup-shaped filter, again fitting over the nose and mouth, and looking like a disposable dust respirator.

They are also known as comfort or hygiene masks and are often wrongly used as a cheap alternative to disposable face mask respirators.
They are often identifiable by only having one strap and the filter is not marked with a protection factor (e.g. P1, P2 or P3).

They should not be confused with approved disposable dust masks which will bear the appropriate EN number and a protection factor.

It should be noted that nuisance dust masks are not classed as personal protective equipment or respiratory protective equipment. They do not meet any current standards or legislative requirements. They should not be issued or used in any circumstances where the COSHH Regulations apply or may apply, where other regulations require the provision of respiratory protection, or where a risk assessment under The Management of Health and Safety at Work Regulations 1999 (as amended) indicates the need for respiratory protective equipment.

People who work with harmful dusts should always be provided with and use the correct type of CE-marked dust masks or respirators to ensure proper and effective protection.

Half-mask dust respirator

This is one of the most common types of respirator used. It consists of a face mask which covers the nose and mouth of the wearer, and a suitable filter through which air is drawn by breathing.

The main advantages of this type of respirator are its low cost, easy maintenance, and the fact that it provides the wearer with freedom of movement.

High efficiency dust respirators

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The filtering canisters or cartridges used in these respirators may be round, oval or triangular, and are often colour-coded to indicate the type of contaminant they give protection against. If a ‘use by’ date or shelf life is specified, it must be adhered to.

High efficiency dust respirators provide full protection by drawing air in through the filter system by inhalation.
Proper fitting and use of the facepiece, and regular maintenance of the respirator in general, are essential if the equipment is to give effective protection.

Positive pressure powered respirators

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A positive pressure powered respirator is one where the air pressure within the mask facepiece is higher than normal air pressure, thus preventing the entry of dust or fumes into the facepiece.

These respirators are most suitable for specialised applications, particularly where long periods of exposure are involved. The air supply to the wearer is provided by a small, battery-operated pump and filter unit which will deliver air continuously for approximately seven hours.

Pressure-assisted air to the operator results in less fatigue, particularly when engaged in strenuous work over long periods.

Batteries must be changed or recharged and filters cleaned or replaced at scheduled intervals to maintain peak efficiency.

Note: When respiratory protective equipment is to be used, it should be remembered that facial hair and spectacles often prevent a respirator from fitting properly and thus achieving the assumed degree of protection.

Ventilated visor and ventilated helmet respirators

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In this type of equipment, a small axial fan housed in the back of the helmet draws in dust-laden air through a series of filters situated in the crown of the helmet. Filtered air is then passed downwards over the user’s face, maintaining a positive pressure in the region of the nose and mouth. The unit is powered by a rechargeable battery pack worn on a belt.

This type of respirator is comfortable and combines protection against dust with the protection afforded by a safety helmet (manufactured to BS EN 397) and face and eye protection (to BS EN 166). It does not provide adequate protection against asbestos, lead alkyls, lead fumes or lead dust above certain specified concentrations. Efficient maintenance and cleansing procedures are essential. If the flow of air is reduced by clogged filters or low battery power, unfiltered air can be drawn in around the side of the facepiece.

Compressed air line breathing apparatus

With this equipment, air is supplied to the user from a compressed air supply, via a hose to the face mask or hood. The correct air pressure, temperature and humidity must be maintained.
The air supplied must be of breathable quality, thus the selection, siting and maintenance of the compressor and filtration of the air supply is vitally important.

The presence of an air hose can, on some occasions, restrict the user’s movements.
As with all types of breathing equipment, operators should be properly and adequately trained and, unless experienced in the type of work to be carried out, should be properly supervised.

Self-contained breathing apparatus

In a set of self-contained breathing apparatus, air is usually supplied from compressed air cylinders carried on the worker’s back and is fed to a full face mask via a regulator. As with the air line apparatus, operators must be properly and adequately trained and, unless experienced in the type of work to be carried out, must be properly supervised.

As the usual duration of a cylinder of compressed air may vary from 20 minutes up to two hours, they can have limited usage. The equipment should therefore only be selected by competent persons with a full knowledge of the subject.

Dust sampling

Sampling is usually carried out by consultants, using metered pumps with membrane filters.
The dust collected is weighed in relation to the amount of air sampled. Dust samples can also be examined for type. There are also some direct-reading dust sampling monitors available.

Use of Tyndall Beam to identify dust clouds

The Tyndall Beam is a useful way to determine whether a problem exists before investigating further. It uses the common phenomenon of dust highlighted in a shaft of light.

Training and supervision

Information, instruction, training and supervision, as required by The Health and Safety at Work etc. Act 1974 and The Management of Health and Safety at Work Regulations 1999 (as amended), must be provided for personnel who work in dusty conditions, including for those with supervisory functions. New employees should receive full instruction before starting work, and should be familiarised with the following:

  • the health risks associated with dust and the preventative measures in operation, as identified by the risk assessment
  • the correct use and cleaning of protective clothing and equipment
  • the reasons for air sampling
  • their duties in respect of the correct use of equipment and of safe systems of work in operation
  • the procedures for reporting defective or inadequate equipment.

Control of fumes

Within the wide range of activities carried out in the construction industry there are numerous operations which liberate fumes into the atmosphere and cause risks to the health and safety of people at work. Every effort must be made to minimise these risks. Under the provisions of the COSHH Regulations, fumes may be classified as a substance hazardous to health and thereby require an assessment of the risk to health to be carried out.

If a risk does exist, control measures such as mechanical extraction systems and adequate natural air ventilation can prevent high concentrations of fumes forming to create a hazard, particularly in confined areas.

The HSE publication EH40 ‘Occupational exposure limits’ lists a level of exposure for each type of fume or pollutant. This represents the maximum limit at which it is considered safe for work to take place.

Every reasonably practicable measure should be taken to reduce any exposure as far below the limit given as is possible.

If the fume type is listed in EH40 or is otherwise a hazard to anyone’s health, the provisions of the COSHH Regulations will apply. Therefore an assessment of the risk and the provision of any necessary precautions must be made.

Some of the more common causes of fumes are listed below and discussed under subsequent headings:

  • welding or flame cutting
  • lead burning (both cutting and melting)
  • cable burning (this practice must not be carried out on site)
  • the use of solvents, paints, adhesives, etc.
  • internal combustion engines.

Welding

During welding and flame cutting, toxic fume hazards can arise from:

  • nitrogen oxide gases
  • ozone
  • phosgene gas
  • carbon monoxide gas.

These are mainly caused by the very high temperatures and the presence of volatile substances, sometimes as contaminants, but often as shielding agents or flux.
The inhalation during welding of freshly formed metal oxides (such as zinc, cadmium, chrome, nickel, copper and mercury) may lead to an acute ‘flu-like’ illness termed ‘metal fume fever’.

The fever is most commonly caused by fumes created while working with galvanised or zinc-coated metals, especially in confined spaces.

Fumes arising from the cutting and welding of cadmium are especially dangerous, even in the open air. Prolonged or recurrent exposure may result in cadmium poisoning.

Precautionary measures

  • A risk assessment, including a COSHH assessment, as appropriate
  • The use of extraction systems and fume hoods to remove fumes from the breathing zone.
  • The use of respiratory equipment, particularly in confined spaces where high concentrations of fumes can be anticipated.

Lead burning

Lead burning is the process whereby lead is heated to its molten state so that it can be poured into joints, or flame cut to shape, or flame heated so that it can be bent and formed into various shapes.

This process is employed extensively in sheet lead work by workers in the plumbing trades, in the formation of roof drainage, guttering, chimney flashings, etc. It is usually a significant exposure and therefore comes under The Control of Lead at Work Regulations 2002.

The creation of fumes by the heating of lead exposes operatives to risk. The following safety points should be observed:

  • the use of local exhaust ventilation or other means to evacuate fumes from the immediate working area where reasonably practicable
  • the use of respiratory equipment of an approved type in the appropriate cases
  • the provision of protective clothing and storage for that clothing, along with adequate washing facilities, etc.

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Wear respirator

Cable burning

This method of recovering metal from cables, by burning off the insulation, often results in the creation of fumes which can be very toxic. Such operations require the place of work to be registered under the Alkali Act and render it liable to additional inspections. The COSHH Regulations will also apply. As stated earlier, this practice is now illegal when carried out on site.
Reference:
The Control of Pollution Act 1974, Section 78

Solvents

Chlorinated solvents, paints, adhesives and thinners all require precautions to be taken during their use. Most, if not all, of these substances are covered by the COSHH Regulations.

Avoid breathing the vapour

Most solvents are safe when used correctly but, in common with other compounds of hydrocarbons, the inhalation of a high concentration of vapour will cause drowsiness, headaches and giddiness. Severe exposure may lead to unconsciousness or even prove fatal. Extraction or exhaust ventilation may be needed or, where this is not available, respiratory protective equipment.

Some of the vapours are considerably heavier than air and may collect at low levels, particularly in still conditions. This can cause displacement of the oxygen present and can lead to the risk of suffocation.

Other precautions with solvents

DO NOT

  • take solvents internally or ‘sniff’ any solvent
  • smoke when using solvents
  • use the solvent in a place which is not well ventilated – but avoid draughts
  • lean over any vessel containing the solvent liquid or vapour
  • store solvents in buckets or other open storage vessels
  • enter vessels which have contained or have been cleaned with solvents, unless proper tests have been made to ensure it is safe to do so
  • allow solvent liquid or vapour to come into contact with naked flames or red hot surfaces, e.g. welding arcs. Acidic and toxic decomposition products will be formed.

Internal combustion engines

Internal combustion engines should not be used within confined spaces unless the exhaust gases are led directly to the open air.
Where air may become deficient or contaminated by exhaust gases in such places as excavations, pits, shafts and tunnels, special care should be taken to ensure adequate ventilation is provided.

In large buildings, such as stores and warehouses, the use of forklift trucks and other vehicles with internal combustion engines can cause carbon monoxide to reach unacceptable levels, if there is no system to extract exhaust pollution. The provisions of The Provision and Use of Work Equipment Regulations 1998 (as amended) should be considered in cases such as this, with regard to equipment being suitable for the work in hand.

In all cases of doubt, an assessment should be made under the COSHH Regulations by a competent person and, where necessary, the appropriate controls introduced.


Control of fumes

Safety checklist

  • An assessment has been carried out that fulfils the requirements of The Management of Health and Safety at Work Regulations 1999 (as amended) and the COSHH Regulations.
  • All hazardous processes and operations have been identified.
  • All personnel have been fully instructed in the types of hazard likely to be encountered.
  • There is adequate supervision of all work operations.
  • All personnel are competent to carry out the work operations.
  • Correct and adequate protective clothing is provided and used.
  • Respiratory protective equipment is provided and used, as necessary.
  • Exhaust ventilation or extraction equipment is used, as required.
  • The correct type of eye protection is provided and used, as necessary.
  • Safe working methods are being adhered to.
  • No-one under 16 years is employed (lead burning).
  • Chlorinated solvents, paints, adhesives, etc. are:
    a) stored safely
    b) used safely.
  • Personnel have been made aware of the hazards that exist when working with chlorinated solvents, paints, adhesives, etc.
  • Engine exhaust gases are led directly out of confined spaces.

Dust hazards

Safety checklist

  • There is compliance with the COSHH Regulations.
  • There is adequate supervision of all work operations.
  • Materials, substances and associated hazards have been properly identified.
  • Manufacturers’ or suppliers’ instructions are available and observed.
  • Power tools are fitted with a dust extraction and collection facility.
  • Local exhaust ventilation is fitted to workshop machinery.
  • The correct protective equipment is supplied and clothing provided.
  • Operatives have been instructed in the use of materials and are aware of the hazards associated with those materials.
  • There is provision for the ongoing training of employees.
  • There is provision for/and operation of safe systems of work.
  • There is adequate provision of washing facilities, and facilities for storing overalls, etc. during meal breaks.
  • Correct procedures for the storage, identification and disposal of waste materials or substances are followed.
  • Adequate arrangements have been made for air sampling, as necessary.

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