SAFed Health and Safety Passport Scheme

Module 7 ó Occupational Health

7.1              Introduction

This document forms one of a series of modules on various health and safety subjects that comprise the examinable material considered necessary for the award of the SAFed Health and Safety Passport.

When you have studied this module you should have acquired sufficient knowledge to be able to answer the questions detailed at the end of the module.  Upon satisfactory completion of all modules, you will be eligible to undertake the final assessment for the award of the SAFed Health and Safety Passport.

The SAFed Health and Safety Passport is issued to Engineer Surveyors by the Health and Safety Manager of their employing company upon satisfactory completion of the Safety Passport final assessment.

The award of the SAFed Health and Safety Passport provides evidence that the holder of the Passport has the appropriate knowledge and awareness in health and safety matters considered necessary for an Engineer Surveyor to undertake the duties for which they are authorised by their employing company.

The passport is valid for a maximum of three years.

7.2       Key Objectives

Having studied this module you should have an awareness of:

         Legislation applicable to Occupational Health

         Occupational health risks.

7.3       Legal Commentary

The Control of Substances Hazardous to Health Regulations 2002 is aimed at the management of hazardous substances within the workplace.  A substance, which is hazardous, is simply any substance or mixture of substances (a preparation), which can damage health either directly or indirectly.

The Control of Lead at Work Regulations 2002 apply to any work activity which is liable to expose employees (or any other person) to lead which can be inhaled, ingested or absorbed.

The Control of Asbestos at Work Regulations (Regulation 9) requires employers to provide adequate health and safety training for employees who are liable to be exposed to asbestos or who carry out work on asbestos, so that risks to all staff are minimised

The Noise at Work Regulations 1989, which came into effect on the 1st January 1990 outlines the responsibilities of both employers and employees with respect to noise hazards in the workplace.

7.4            Discussion

Typically in the workplace the following might be categorised as hazardous substances:

         welding fume resulting from the joining, cutting, removal of metals;

         specialist chemicals used in the manufacturing of other chemical agents;

         cleaners and degreasers used for removing fuel oil, grease and lubricants;

         specialist paints; and

         solvents (e.g. NDT aerosol fumes, cleaning brushes, white spirit)

         airborne dusts (e.g. silica, metallic, foundry dusts etc)

Once the hazardous substances within the working area have been identified, and ideally an inventory made, the next action is to carry out a risk assessment to estimate the risks involved in handling or being exposed to the particular substance.

7.5            Significant Hazards

There are 3 routes of exposure by which hazardous substances can cause harm:

i)                    through ingestion (i.e. swallowing);

ii)                  by inhalation (i.e. breathing in fume), and

iii)                 absorption (i.e. penetration through the skin).


Ingestion involves the swallowing of a liquid or solid substance.  It is not likely that a worker will deliberately do this; harm to health would arise through contamination.  Therefore to avoid this, good housekeeping, for instance frequent washing and eating well away from the working area should be encouraged.


Inhalation is probably the major route of exposure to a hazardous substance, and although the form of the substance could be a solid (e.g. wood dust), it is more likely to be a vapour or fume.  The vapour or fume could be generated from a specific process where local exhaust ventilation was either ineffective or altogether absent, or could arise from general background levels within a workshop.


Absorption of a substance normally involves penetration of the skin by a liquid, although absorption through mucous membranes, such as the eye can occur.  The unbroken skin normally acts as an effective barrier against the penetration of substances, but a number of known chemicals, including some common solvents (e.g. methanol, xylene) found in products possibly used in the working area, can be absorbed through the skin.

7.6       Who is at Risk?

As would be anticipated, the member of staff actually engaged in the process where the hazardous substance is used or generated, will be at the greatest risk of being harmed.  However, there could be other workers who are also exposed, including those taking part in maintenance activities or staff simply being in the area where the hazardous substances are present.  These workers may be at greater risk, since they could be less aware of the precautions to be taken (e.g. the wearing of personal protective equipment) and the correct action to be taken in the event of an emergency such as a major spillage.

The mishandling of hazardous substances or their unnecessary generation, and their use in a poorly controlled system has the potential to affect both workers not directly involved in the specific process and non-members of staff.  The latter will include visitors, contractors and possibly members of the public. It is worth noting, that whilst the employee actually working with the hazardous substance might have been issued with personal protective equipment (PPE), this is of little protection to the visitor or contractor.

7.7            Common Risks Involved

Going to work carries a risk of injury or illness.  Besides accidents, people work with chemicals that can cause for example asthma and dermatitis, and do work that can trigger conditions.

If you work with hazardous chemicals your employer has to keep airborne dust or fumes within the limits set by law and in some cases has to arrange regular medical checks for you.  When an illness is caused by work, or when there has been a serious injury, your employer has to report this to the Health and Safety Executive (HSE).


Asthma is a very common long-term condition.  It can be so mild that it's hardly noticeable or it can come on suddenly and be so severe that the affected person may panic.  Asthma affects the breathing, making it harder to get enough breath, and causing wheezing, coughing and a strong feeling that the air can't get in or out of the lungs.  This feeling is caused when the airways narrow.

Sometimes coughing is the main effect and the person concerned may not realise that the problem is asthma.  Often it's easier to breathe in than to breathe out, so the lungs remain too full of air and can't easily be emptied.

Wheezing and noisy breathing are common features of an asthma attack, and during an attack there is a feeling of tightness of the chest, and the heart may be beating more quickly than usual.

Breathing in, or contact with, quite a number of different things can start an asthma attack.

These include:

         Pollens or fungal spores

         Viral and bacterial chest infections

         Animal allergen or house dust mite

         Food additives, such as tartrazine

         Seasonal changes

         Strong smells or perfumes

         Smoke pollution, or vehicle exhaust fumes

         Worry and stress

         Some medicines, especially beta-blockers and aspirin




         Some fruits

         Heavy exercise, especially when it's cold.

The forms of asthma can be divided into two groups Ė those with a known cause and those without.  The first group mainly affects people with a general condition called atrophy.  This is a genetic condition that makes people allergic to various substances (allergens).  It also increases the likelihood of eczema and hay fever and there is often a family history of these conditions.

The second group are more likely to have developed asthma as a result of exposure to industrial or atmospheric pollution, or drugs such as NSAIDs (non-steroidal anti-inflammatory drugs) and beta blockers.  Well over 200 industrial substances are known to bring on asthma.

People with atrophy are also more likely to develop asthma in response to industrial and other pollutants than are people who do not have atrophy, and to do so more quickly.


Dermatitis is a general term meaning inflammation of the skin.  Dermatitis, of which eczema is a form, can be any one of a considerable range of disorders in which the skin is inflamed.  However, contact with chemicals is a common cause of this disorder.

Whatever the cause, the signs and symptoms of dermatitis are similar, but they may range widely in severity.  They include:


         blister formation,


         weeping and crusting, and

         itching and burning.

         Scratching often makes the condition worse, and may in itself keep it going.

Different kinds of dermatitis may have a similar appearance, but the causes may be very diverse.  There is no difficulty in diagnosing dermatitis, as it is apparent from the appearance of the skin.  The difficulty is in finding the cause and treating it.

Many forms of contact dermatitis can be prevented by placing a barrier between the skin and the cause, or by trying to keep away from it altogether.  Rubber or plastic gloves can be a great help unless you are allergic to the material of the gloves.

7.8       What is the Law?

Systems of work involving the use of substances hazardous to health must be safe, so far as is reasonably practicable, under the requirements of Section 2 of the Health and Safety at Work etc. Act 1974.  Under the Control of Substances Hazardous to Health Regulations 2002 employers are required to make arrangements to control the exposure of their employees to all substances, which may affect their health.

Exposure must be prevented or, where this is not reasonably practicable, adequately controlled.  The Regulations include measures relating to the control of harmful micro-organisms and arrangements for notifying the HSE when biological agents are first used in the workplace.

The principle objective of the Control of Lead at Work Regulations 2002 is to prevent workplace disease resulting from exposure to lead dust, fume or vapour, which may be inhaled, or lead in a form in which it is liable to be ingested or absorbed through the skin. Basic occupational hygiene principles are followed by the Regulations which introduce a control framework by requiring an adequate assessment of the risks to health arising from work activities associated with lead, the introduction of adequate control measures, maintenance of the measures and equipment associated with them, and monitoring the effectiveness of the measures and the health of employees.

The inhalation of asbestos fibres may cause asbestosis, lung cancer and mesothelioma, employers have a general duty under the Health and Safety at Work etc Act 1974 to provide training to ensure the health, safety and welfare of their employees, so far as is reasonably practicable, these duties have been made more explicit by the Control of Asbestos at Work Regulations 2002, the regulation adds a further duty to manage asbestos in non-domestic premises.

Section 2 of the Health and Safety at Work etc Act 1974 requires employers to provide a safe working environment, more specific duties are imposed on the employer by the Noise at Work Regulations 1989, which defines certain action levels based on personal daily noise exposure levels of employees.

Personal protective equipment, when used to control exposure, must be considered as a last resort but, if necessary, steps must be taken to ensure proper use by the employee (Regulations 7 / 8).  This equipment must conform to the requirements of the Personal Protective Equipment at Work Regulations 1992.

7.9       Air Monitoring

Essential to the practice of occupational hygiene is the use of standards for the assessment of measurements made in the workplace.  An equally important part of an occupational hygiene programme is the measurement of the extent of the hazard.  This is generally done by measuring physical and / or chemical factors, including exposure duration, and relating them to occupational hygiene standards.  Health hazards often reveal their effects on the body only after the passage of time, because the effects are often not immediately apparent, it can be difficult to understand and persuade others that there is need for caution and control.


Monitoring is carried out for a number of reasons:

         to check on the condition of control measures;

         to assist in the design of new or improved control measures; and

         to help set the specification for new controls on a process.

[Note:  Carrying out monitoring is not an alternative to controlling exposure, if in doubt; the resources should always be put into improving control in an area rather than measuring exposure]

Occupational Exposure Limits (OEL)

The Health and Safety Executive (HSE) publishes guidance note EH40 annually, reproducing the current statutory list of Maximum Exposure Limits (MELís) and approved Occupational Exposure Standards (OESís).

[Note:  It is important to see that the current document is the one consulted]

The exposure of employees to substances hazardous to health is to be prevented or, where this is not reasonably practicable, adequately controlled is a fundamental requirement of the Control of Substances Hazardous to Health Regulations 2002 (CoSHH).

[Note:  EH40 lists the limits to be used in determining the adequacy of the control of exposure by inhalation]

Advice and data in EH40 is to be taken in the context of the CoSHH Regulations, especially Regulation 6 (Assessment), Regulation 7 (Control of Exposure), Regulations 8 and 9 (Use and Maintenance, Examination and Testing of Local Exhaust Ventilation) and Regulation 10 (Monitoring of Exposure).

[Note:  There is separate legislation for lead and asbestos, these substances are not covered in detail in EH40]

Maximum Exposure Limits / Occupational Exposure Standards

MEL is the maximum concentration of an airborne substance, averaged over a reference period (e.g. 8-hour long term) to which employees may be exposed by inhalation under any circumstances. OES is the concentration of an airborne substance, averaged over a reference period, at which there is no current evidence that repeated exposure by inhalation will be injuries to the health of employees.

Regulation 7 of CoSHH sets out requirements for the use of MELís and OESís for the purpose of achieving adequate control.

Regulation 7(4) requires that where there is exposure to a substance for which an MEL has been assigned, the control shall, so far as inhalation of that substance is concerned, only be treated as adequate if the level of exposure is reduced as far as is reasonably practicable and in any case below the MEL.  Regulation 7(5) requires that, without prejudice to the generality of Regulation 7(1), where there is exposure to a substance for which an OES has been approved, the control of exposure shall, so far as the inhalation of that substance is concerned, be treated as adequate if the OES is not exceeded, or where the OES is exceeded, the employer identifies the reasons for the standard being exceeded and takes appropriate action to remedy the situation as soon as is reasonably practicable.

Sampling Method

Methods for the sampling and analysis of many substances which have been assigned MELís / OESís are described in the HSE series, Methods for Determination of Hazardous Substances (MDHS).

Evaluation of Results

The confidence one can place on the results of a sampling programme is a function of many variables; consequently, the results are more appropriately treated, at least initially, as guidelines for further action rather than as an unequivocal measure of observance or non-observance of the standard. Moreover, the numerical results of the survey need to be interpreted in conjunction with the data obtained in the initial appraisal and in relation to the work activities in progress and the conditions pertaining at the time of the survey.

7.10     Noise

The Noise at Work Regulations 1989 came into effect on the 1st January 1990.  The Regulation outlines the responsibilities of both employers and employees with respect to noise hazards in the workplace.

In essence, the Regulations require the following important actions:-

i)                    When the daily exposure level of persons reaches or exceeds the first action level of 85dB(A), when averaged over 8 hours (called Lep,d. for short), the employer should make hearing protection available to anyone who wishes to use it.  He should also advise employees about the nature of the noise hazard, where and when             it occurs, and what precautions need to be taken.

ii)                  When the daily exposure level of persons reaches or exceeds the second action level of 90dB (A), in addition to the training measures outlined above, the employer should declare all such areas as hearing protection zones (where the wearing of hearing protection is obligatory), and these should be suitably marked with signs.  He should also carry out noise control work to reduce the noise to the lowest level reasonably practicable.

iii)                 In addition, even if the second action level of 90dB (A) is not exceeded, when averaged over an 8 hour day, but the peak action level is reached (140dB re 20u Pa), then the measures outlined in ii. above have still to be met.

Scope of the Regulations

The Regulations apply to all workers in Great Britain governed by the Health and Safety at Work etc. Act 1974, except the crews of seagoing ships and aircraft moving under their own work-power.

Assessing and Recording Noise Exposure

Employers are required to assess noise exposure if it is likely that employees will be exposed above the first or peak action levels:-

a)      to ensure that everyone likely to be exposed is identified.

b)      to obtain enough information to guide the action required by the Regulations.

Background to Noise Exposure Measurement

The objective of industrial noise control and hearing conservation programmes is to protect employees from permanent hearing loss in the speech frequency range due to exposure to high noise levels.

When we are exposed to high noise levels, even for short periods, we experience a temporary hearing loss known as a temporary threshold shift.  You may have noticed this after leaving a stock car race or a discotheque.  But our hearing soon recovers under normal conditions.  However, when employees are exposed to high noise levels every working day for many years, they gradually develop a permanent hearing loss known as a permanent threshold shift.  Because the loss develops over a long period, noisy environments are considered to be more of a health hazard than a safety hazard (they do however become a safety hazard when they mask audio warning signals).

Most industrialised countries have established limits for occupational noise exposure.  These exposure limits protect most, but not all employees who are exposed to high noise levels. Assurance of complete protection is the objective of any hearing conservation programme.

Hearing conservation programmes use periodic hearing tests to identify employees who are highly susceptible to noise induced hearing loss.  These employees can then be given extra hearing protection or assigned to quieter working areas.  Successful programmes protect employees from noise induced hearing loss and employers from compensation claims for hearing loss.

Frequency Analysis

Acoustically treated surfaces, noise enclosures and ear protectors are all more efficient at some frequencies than at others.  Therefore, the frequency spectrum of the environmental noise must be measured first before selecting ear protectors or absorbing materials.  For the same reason the frequency spectrum of a machine must also be measured first in order to design an enclosure or a noise barrier.  Frequency analysis is also valuable in proving the effectiveness of installed enclosures and in trouble-shooting during their installation. In general, Octave Band Filters are used for these purposes and are therefore an essential part of noise control instrumentation.

Ear Protectors

Ear protectors reduce the amount of noise actually entering the ear canal.  Some national standards permit their widespread use, whereas others limit their use to an interim measure until engineering methods of noise control are carried out and in cases where engineering control is not feasible.

The effectiveness of earplugs and earmuffs depends upon how well they fit and how carefully they are worn.  A loss of attenuation of up to 10 dB can occur if the path to the ear canal is not tightly sealed.

As with any acoustic barrier, different types of ear protectors have different curves of noise attenuation verses frequency.  Therefore, ear protectors should be selected by matching their attenuation characteristics to the octave band analysis of the sound field.

Low-cost Noise Control

Noise control procedures need not be expensive.  There are many examples of low-cost noise control, and some which can even reduce operating costs.

A common administrative procedure is personal rotation.  In high noise environments where noise control is impractical, the work, and consequently exposure, can be shared among several employees who otherwise work at quieter workstations for the rest of the day.

Compressed air leaks are significant noise sources in many industries.  Another source of noise is the use of air pressures far greater than necessary to perform tasks such as parts ejection and swarf blow-off.  When leaks are repaired or pressure reduced, noise levels drop: so too does energy consumption, this is a good example of noise control reducing operating costs as well as noise levels.

Lowering hydraulic pressures used to form or cut metal parts can often reduce press noise.  There are prospects too of lowering costs through longer tool life.

Marginal over-exposure can often be avoided at low cost by replacing metal tote pans by ones made of hard rubber, by tightening loose parts on machines and by replacing defective mufflers and ineffective vibration mounts.

The list of low-cost noise control goes on and on.  Noise control engineers should exhaust these methods before turning to more expensive procedure.

7.11     End of module and next steps

Well done!  By reaching this point you will have finished studying this particular module.  You should now have sufficient knowledge to answer the questions contained at the end of the module.

Answers to the questions should be forwarded to your Health and Safety Manager.

Provided that you have answered the questions correctly, your Health and Safety Manager will forward to you your next self study module.

Click here to answer questions on Module 7