13. Physical and psychological hazards

The following can cause physical and/or psychological harm:

  • Ionising and non-ionising radiation;
  • Noise;
  • Vibrations;
  • High or low temperatures;
  • High humidity;
  • Poor ergonomics – body position;
  • Repetitive actions;
  • Fatigue;
  • Stress.

Physical health hazards

Ionising radiation

Ionising radiation occurs as either electromagnetic rays (such as X-rays and gamma rays) or particles (such as alpha and beta particles). It occurs naturally (e.g. radon gas) but can also be produced artificially. Everyone receives some exposure to natural background radiation.

It is used or occurs in the following work settings:

  • Medicine (for diagnosis and treatment);
  • Industry (for measurement and non-destructive testing);
  • Power generation (nuclear power stations);
  • Research and teaching.

Exposure to ionising radiation can alter human cells. It can cause radiation burns, poisoning and lead to cancer. It can be dangerous to unborn babies.

Exposure can be directly from a source of ionising radiation. Consequences can be particularly severe when radioactive material is ingested as the exposure lasts as long as the material is inside the body.

Ionising Radiations Regulations 2017 require employers to make sure exposure is restricted as far as reasonable practicable and is kept below dose limits. Practices must be authorised by the HSE and suitable risk assessments need to be carried out prior to work commencing and reviewed at suitable intervals. Where radiation accidents are reasonably foreseeable, contingency plans need to be developed. The latest version of the regulations requires that procedures are in place to estimate doses to members of the public

Employers need to appointment Radiation Protection Advisers (often an individual from a specialist company) who achieve competence in the management of risk due to ionising radiation. They should be consulted with to ensure regulations are being complied with.

The regulations specify circumstances when controlled areas need to be defined because people may be exposed to certain levels of ionising radiation within them. Where such areas are necessary it is a requirement to develop ‘Local Rules’ and appoint Radiation Protection Supervisors who have a fundamental role in ensuring compliance with regulations and local rules. They do not need to be present at the worksite at all times, but are the first point of contact for help and advice and so need to be readily available.

People who have the potential to be exposed to certain levels of ionising radiation need to be designated as a ‘Classified Person’ and their dose must be monitored and records kept. Action needs to be taken where someone is exposed to excessive doses of ionising radiation.

Reference – Approved Code of Practice L121 ‘Work with ionising radiation’ available free at http://www.hse.gov.uk/pubns/priced/l121.pdf

Non-ionising radiation

Non-ionising electromagnetic radiation (NIEMR) is the term used to describe the part of the electromagnetic spectrum covering two main regions

1. Optical radiation including ultraviolet (UV), visible light and infrared. Hazardous exposure may result from the sun, sunbeds, lasers and welding.

2. Electromagnetic fields (EMFs) including power frequencies, microwaves and radio frequencies.

Exposure of the eyes to UV radiation can damage the cornea and produce pain and symptoms similar to that of sand in the eye. The effects on the skin range from redness, burning and accelerated ageing through to various types of skin cancer.

High-power lasers can cause serious damage to the eye (including blindness) as well as producing skin burns.

Exposure of people to high levels of EMFs can give rise to acute effects. The effects depend on the frequency, with low frequencies affecting the central nervous system and high frequencies causing heating effects that can lead to a rise in body temperature. In reality, these effects are extremely rare and will not occur in most day-to-day work situations


Noise at work can cause hearing loss. This may be temporary, but continued exposure, or short term exposure to very high noise can cause permanent damage. Also, exposure to high levels of noise can cause tinnitus (ringing, whistling, buzzing or humming in the ears) and working in a noisy environment makes communication difficult and can mean people cannot hear warnings and alarms.

Noise levels are measured in Decibels (dB). Control of Noise at Work Regulations 2005 set limits for short and long term exposure and require employers to:

  • Assess the risks to their employees from noise at work;
  • Take action to reduce the noise exposure that produces those risks;
  • Provide employees with hearing protection if the noise exposure cannot be reduced enough using other methods;
  • Make sure the legal limits on noise exposure are not exceeded;
  • Provide employees with information, instruction and training;
  • Carry out health surveillance where there is a risk to health.

Legal limits are defined in three categories

1. Lower exposure action values which are a daily or weekly exposure of 80 dB or peak sound pressure of 135 dB – above these levels hearing protection must be available for employees (although they do not need to use it) and information and training must be given regarding the risks and controls;

2. Upper exposure action values which are a daily or weekly exposure of 85 dB or peak sound pressure of 137 dB – above these levels the noise must be reduced to as low as reasonably practicable and employees must wear hearing protection;

3. Maximum exposure limit values which are a daily or weekly exposure of 87 dB or peak sound pressure of 140 dB – exposure must not exceed these levels.

A key element of the regulations is that noise levels should be reduced before considering hearing protection. Employees have a duty to co-operate with their employers in protecting hearing, including wearing hearing protection provided.

Reference – ‘Noise at work Guidance for employers on the Control of Noise at Work Regulations 2005’ available free at http://www.hse.gov.uk/pubns/indg362.pdf

Reference – L108 ‘Controlling noise at work’ available free at http://www.hse.gov.uk/pubns/priced/l108.pdf


There are two main concerns regarding vibration:

1. Whole body vibration;

2. Hand arm vibration.

Whole-body vibration is shaking or jolting of the human body through a supporting surface (usually a seat or the floor), for example when driving or riding on a vehicle along an unmade road, operating earthmoving machines or standing on a structure attached to a large, powerful, fixed machine which is impacting or vibrating. It can cause back pain, often aggravating a previous problem.

Hand-arm vibration can be caused by operating hand-held power tools (e.g. road breakers), hand-guided equipment (e.g. powered lawnmowers) or by holding materials being processed by machines (e.g. using pedestal grinders). Regular and frequent exposure to hand-arm vibration can lead to permanent health effects (occasional exposure is unlikely to cause ill health). Symptoms include:

  • Tingling and numbness in the fingers;
  • Not being able to feel things properly;
  • Loss of strength in the hands;
  • The fingers going white (blanching) and becoming red and painful on recovery (particularly in the cold and wet, and probably only in the tips at first).
  • Continued exposure can mean people cannot use their fingers properly, especially in cold conditions.

The Control of Vibration at Work Regulations require employers to:

  • Assess the vibration risk to employees;
  • Decide if they are likely to be exposed above the daily exposure action value (EAV), and if so introduce a programme of controls to eliminate risk, or reduce exposure to as low; and provide health surveillance
  • Decide if they are likely to be exposed above the daily exposure limit value (ELV) and if they are take immediate action to reduce their exposure below the limit value;
  • Provide information and training to employees on health risks and the actions you are taking to control those risks;
  • Consult trade union safety representative or employee representative on your proposals to control risk and to provide health surveillance;
  • Keep a record of risk assessment and control actions;
  • Keep health records for employees under health surveillance;
  • Review and update your risk assessment regularly.

The exposure action value (EAV) is a daily amount of vibration exposure above which employers are required to take action to control exposure. For hand-arm vibration the EAV is a daily exposure of 2.5 m/s2 A(8) and for whole body vibration 0.5 m/s2 A(8)

The exposure limit value (ELV) is the maximum amount of vibration an employee may be exposed to on any single day. For hand-arm vibration the ELV is a daily exposure of 5 m/s2 A(8) and for whole body vibration 1.15 m/s2 A(8)

Reference – ‘Control back-pain risks from whole-body vibration’ available free at http://www.hse.gov.uk/pubns/indg242.pdf

Reference – ‘Control the risks from hand-arm vibration’ available free at http://www.hse.gov.uk/pubns/indg175.pdf

Reference – L140 ‘Hand-arm vibration’ available free at http://www.hse.gov.uk/pubns/priced/l140.pdf

Reference – L141 ‘Whole-body vibration’ available free at http://www.hse.gov.uk/pubns/priced/l141.pdf


Working in conditions that are too hot can cause heat stress that can affect a person’s ability to work, potentially leading to heat exhaustion and heat stroke (can result in unconsciousness and can be fatal). Also, dehydration.

Working in cold conditions can cause cold stress and hypo-thermia.

Temperatures in the workplace are covered by the Workplace (Health, Safety and Welfare) Regulations 1992. Employers must provide a “reasonable” temperature in the workplace.

It is suggested that the minimum temperature in workrooms should normally be at least 16 degrees Celsius, or 13 degrees Celsius if much of the work indoors involves severe physical effort. A meaningful figure cannot be given at the upper end of the scale because other factors have an affect including radiant temperature, humidity and air velocity.


Humidity is the amount of water vapour in air. Levels are usually quoted as relative humidity, which is the ratio between the actual amount of water vapour in the air and the maximum amount of water vapour that the air can hold at that air temperature

High relative humidity (>80%) starts to prevent evaporation of sweat from the body. This evaporation is a major way of regulating body temperature. Therefore, high humidity can contribute to heat exhaustion and heat stroke.

Humidity is particularly a concern when people are required to wear extra clothing (i.e. in the form of personal protective equipment). In this case the humidity inside clothing can be significantly higher than outside.

Humidity is covered by the Workplace (Health, Safety and Welfare) Regulations 1992.

Managing the risks associated with physical hazards


Ergonomics is the application of scientific information concerning humans to the design of objects, systems and environment for human use. The aim is to use this information to ensure comfort, efficiency, productivity and safety. Ergonomics comes into everything which involves people. In a phrase, the job must ‘fit the person’ in all respects, and the work situation should not compromise human capabilities and limitations.

Ergonomics covers anatomy, physiology and psychology.

Neck and back pain

Neck and back pain can arise in many situations, but the following are known to cause problems:

  • Heavy manual labour;
  • Manual handling in awkward places;
  • Repetitive tasks;
  • Sitting at a workstation for a long time (especially if not set up properly);
  • Stooping, bending over or crouching (poor posture);
  • Pushing, pulling or dragging excessive loads;
  • Stretching, twisting and reaching;
  • Prolonged periods in one position, leading to postural strain;
  • Situations where the whole body is subjected to vibration, jolting and jarring (including driving long distances or over rough ground).

As with many ill health conditions, some people are more susceptible to back pain than others.

The HSE has dedicated web pages for neck and back pain at http://www.hse.gov.uk/msd/backpain/index.htm

Work related upper limb disorders (WRULD)

WRULD, sometimes known as repetitive strain injury are problems with the shoulder and arm, including the forearm, elbow, wrist, hand and fingers, and can include neck pain. Any type of work that involves a worker using their arms to carry out tasks can lead to WRULDs, although they are frequently associated with computer use and assembly work. Symptoms include tenderness, aches and pain, stiffness, weakness, tingling, numbness, cramp and swelling.

Risk factors include:

  • Repeating an action;
  • Uncomfortable working position;
  • Using a lot of force;
  • Carrying out a task for a long period of time;
  • Poor working environment;
  • Psychosocial issues (lack of control or status).

Finding solutions is not always easy, and it is important to recognise that people are different sizes, have different abilities and some are more susceptible due to disabilities. Certainly workstation and job design can have a significant impact, but behaviours are equally important, including posture, exercise and taking breaks. People need to be informed of the risks and how to minimise them. If someone contracts WRULD it may be sufficient for them to change their working methods. However, in some cases medical treatment and rehabilitation may be required.

Reference- ‘Aching arms (or RSI) in small businesses’ available free at http://www.hse.gov.uk/pubns/indg171.pdf

Display screen equipment (DSE)

Poor physical layout of DSE workstations can cause WRULD. Also, screen glare and poor image quality can contribute to tired or sore eyes and headaches (especially for people who wear contact lenses or bi-focal glasses). People using DSE can suffer from stress due to the expected pace of work or anxiety about new technology.

There is no evidence to suggest radiation from screens is a problem, even for pregnant women. A few people claim skin problems, but this is more likely to be with air quality (that may be affected by electrical equipment) rather than the DSE itself. A small number of epileptics may have problems.

The Health and Safety (Display Screen Equipment) Regulations 1992 require that operators or users have:

  • Adequate training and information;
  • Proper breaks or changes of activity;
  • Work stations suitable for them which meet, where necessary, the standards in the schedule;
  • Eye tests if they request them.

There are many devices available that are designed to minimise health impacts from using DSE. They include specialised computer mice, document holders and arm rests. As with WRULD, whilst these can assist it is often behaviour (combined with well design standard DSE) that can have the greatest impact.

Reference – ‘Working with VDUs’ available free at http://www.hse.gov.uk/pubns/indg36.pdf

Reference – L26 ‘Work with display screen equipment: Health and Safety (Display Screen Equipment) Regulations 1992 as amended by the Health and Safety (Miscellaneous Amendments) Regulations 2002’ available free at http://www.hse.gov.uk/pubns/priced/l26.pdf


Stress is the adverse reaction people have to excessive pressures or other types of demand placed on them. Whilst pressure is an integral part of work and helps to keep people motivated, when it is excessive it can lead to stress. Stress causes chemicals to be released into the body that impact on how the body works. Over time this can cause significant health problems. Also, stress affects peoples’ concentration, information processing and decision making, which undermines their performance and can cause them to commit errors or behave unsafely.

The primary sources of stress at work include:

  • High demands – excessive workload, unhealthy work patterns and working poor environment;
  • Lack of control – no say in the way they do their work;
  • Lack of support – lack of encouragement and resources from the organisation;
  • Poor relationships – tension with management or colleagues and a failure to deal with unacceptable behaviour such as bullying;
  • Poorly defined roles –people not understanding their responsibilities or the scope of their job;
  • Poorly managed change – people not considered in the change management process or not given sufficient information about what is happening or why.

Organisations should have systems in place to manage stress. They should include a policy, organisation and arrangements to identify potential stress (through risk assessment) and actual stress (sickness rates). Also, the organisation and arrangements to deal with the occurrence of stress and potential stress. Proactive monitoring of stress, often through the use of staff surveys, should be part of the arrangements.

The HSE has a website dedicated to stress at http://www.hse.gov.uk/stress/index.htm


Fatigue occurs when people get very tired over a long time and/or are unable to rest. It significantly increases the likelihood of human error and over the long term can cause or contribute to stress (with subsequent health problems). Poor working conditions (e.g. noise, lighting, DSE) tend to increase levels of fatigue.

Shift and night work

Shift and night workers are particularly prone to fatigue because their working patterns differ from natural ‘circadian rhythms,’ meaning they have to be awake when their body wants to be asleep. They are known to be prone to stomach, heart and psychological problems. Also, research has shown that night works may be at higher risks of some forms of cancer and working unusual hours can impact on relationships causing stress.

People working at night are likely to be tired and so prone to errors. Also, it is likely to be dark and there is usually less support (e.g. technical), which can create problems.

Good shift patterns and controls over hours actually worked can minimise fatigue. Plenty of exercise, a healthy diet and getting sleep whenever possible are particularly important for shift and night workers to minimise the risks due to their patterns of work.

Reference – ‘Managing shift work’ available free at http://www.hse.gov.uk/pubns/priced/hsg256.pdf . Also, ‘Specific topic 2: managing fatigue risks’ available free at https://www.hse.gov.uk/humanfactors/topics/specific2.pdf

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