The University is committed to ensuring that staff and students work in healthy and safe conditions. For outdoor work this means minimising exposure to solar radiation and assessing and controlling the hazards of working in seasonal heat.

It is an established fact that the major cause of skin cancer in Australia is exposure to sunlight. The intensity of the ultraviolet [UV] component of sunglight is not directly linked to the temperature or brightness of the sunlight, which means that exposure to sunglight even on cool or cloudy days can still be a hazard. The daily UV intensity is provided in weather forcasts. When the UV index exceeds 3, skin protection is recommended. More information can be found on the SunSmart UV Alert site of the Bureau of Meteorology

When working in hot conditions, the body dissipates excess heat by evaporating sweat and varying the blood flow to the skin. In order to keep the internal body temperatures within safe limits, these responses are automatically controlled by the brain and usually occur if the blood temperature exceeds 37 degrees celsius. Working in hot environments can cause a number of adverse health effects which are generally known as heat stress. Heat stress occurs when the body's heat dissipation mechanisms are unable to prevent body temperature from rising.


The aim of this document is to provide guidance to staff on controlling exposure to the hazards posed by outdoor work - particularly exposure to ultraviolet radiation and work during seasonal heat. The guidelines are applicable to urban outdoor work such as gardening, to farm work in rural areas, and to outdoor field work.
Supervisors and staff for whom these guidelines are intended should discuss them and agree on procedures that are appropriate to their local circumstances and types of work performed.
Further advice can be obtained from your WHS Advisor



  • Basal Cell Carcinomas (BCC) are the most common and least dangerous type. They usually appear on the face and neck, as small round or flattened lumps. They can spread into the surrounding tissues and break down into ulcers if untreated.
  • Cataracts are opacities of the lens of the eye.
  • Heat cramps are painful muscle cramps that can occur on their own or with other heat related illness such as heat exhaustion.
  • Heat exhaustion is a serious condition that can develop into heat stroke. A person with heat exhaustion may complain of weakness, nausea and/or “giddiness”. The person may look pale and be breathless. The skin is usually wet from sweating.
  • Heat fainting occurs when blood vessels (particularly in the legs) dilate in order to increase heat transfer to the skin and cause reduced return blood flow to the heart. This response temporarily reduces blood flow to the brain, which can cause a person to faint.
  • Heat stroke is a medical emergency, caused by a rise in core body temperature. A person suffering heat stroke becomes confused, and may stagger or collapse. Call an ambulance and apply urgent first aid.
  • Heavy work refers to tasks which require continuous intense effort such as continuous shovelling.
  • Keratoses are dry rough spots on the skin, and indicate prolonged exposure to UV radiation. They are sometimes called sunspots. Very occasionally these develop into skin cancers.
  • Light work refers to tasks which require minimum additional effort to walking such as moving hoses around.
  • Melanomas are the least common but most dangerous of the skin cancers. They often start as a new spot, freckle or mole that changes in shape, thickness or colour, and can be a variety of colours, usually with an irregular shape. Existing moles can develop into melanomas. Melanomas can spread to internal organs and can cause death if they are not detected and removed. Some people, with Dysplastic Naevi Syndrome, seem to have an increased risk of developing melanomas.
  • Moderate work refers to tasks which require less intense or less continuous effort such as mowing and intermittent digging.
  • Photokeratitis is inflammation of the cornea.
  • Photosensitisers are substances that cause photosensitivity.
  • Photosensitivity is an abnormally high reactivity in the skin or eyes to UV radiation including natural sunlight. This may be induced by ingestion, inhalation or skin contact with certain substances known as photosensitisers. Symptoms will vary with the amount of UV radiation, type and amount of photosensitiser, skin type, and age and sex of the person exposed.
  • Prickly heat is an intense, itchy red skin rash.
  • Pterygia are growths of tissue on the outside of the eye which can grow over the cornea.
  • Skin cancers - Basal Cell Carcinoma [BCC], Squamous Cell Carcinoma [SCC] and Melanoma.
  • Squamous Cell Carcinomas are less common but more dangerous than BCCs. They often occur on the lips as scaly and red areas that may bleed easily and become ulcerated. They very occasionally spread to lymph nodes.


Solar ultraviolet radiation reaching the earths surface consists of UV-A (315 - 400 nm) and UV-B (280 nm-315 nm). While sunlight contains more UV-A than UV-B, the UV-B component is much more active in causing skin damage. Broad spectrum sunscreens cut out all of the UV-B and at part of UV-A ranges.

Although certain skin types are associated with an increased risk, it is important that everyone should protect their skin from exposure to solar UV radiation, regardless of skin type. Skin cancer is mostly related to the number of severe sunburns, particularly during childhood. But a person's lifetime or ‘cumulative' exposure can also increase their long-term risk of skin cancer.

Solar radiation is most intense between the hours of 10 am and 2 pm Standard Time or 11 am and 3 pm Daylight Saving Time. During the winter months, the sun is lower in the sky and the amount of solar UV radiation received in Australia is less than that received during summer. However if the UV Index is 3 or above, protective measures should still be taken at any time during the year. Note that in tropical North Australia the UV index of 3 is exceeded year round.

Short Term Exposure
Short term or acute exposure to the sun can result in sunburn and injury to the eyes.
The effects of sunburn can range from mild reddening of the skin, to severe blistering, depending upon the duration of the exposure. There is usually a latent period of 8 to 24 hours between exposure and the effects.
As a guide, the effects of exposure of untanned unprotected skin to summer sunlight between 11 am and 3 pm daylight saving time will be:

  • 12 minutes of exposure will cause mild sunburn
  • 30 minutes of exposure will cause appreciable discomfort
  • 60 minutes of exposure will result in blistering and peeling. and
  • 120 minutes of exposure will result in permanent skin damage

Note that there is a wide variation of skin types and those that are more sensitive to ultraviolet (UV) radiation will burn more quickly than the the times stated above. These skin types are also at a greater risk of skin cancer. The following table provides a summary of the range of skin types.

Skin type

Natural skin appearance

Sensitivity to the sun

Tendency to burn

Skin cancer risk


Very fair, pale white skin

Highly sensitive to UV

Always burns, never tans

Greatest risk of skin cancer


Fair, white skin

Very sensitive to UV

Always burns easily, tans minimally

High risk of skin cancer


Light brown skin

Sensitive to UV

Burns moderately, tans uniformly

High risk of skin cancer


Moderate brown skin

Less sensitive

Burns minimally, always tans well

Exposure over a lifetime can still risk skin cancer


Dark brown skin

Minimal sensitivity

Rarely burns, tans profusely

Exposure over a lifetime can still risk skin cancer


Deeply pigmented, dark brown to black skin

Minimal sensitivity

Never burns

Not immune to skin cancer. Skin cancers that do occur are often detected at a later, more dangerous stage

The short term effects to the eyes are:

  • Photoconjunctivitis - inflammation of the conjunctiva
  • Photokeratitis - inflammation of the cornea.

Long Term Exposure
Permanent damage to both the skin and and the eyes can result from prolonged exposure to the sun. The results are:

  • the formation of cataracts,
  • the formation of pterygia,
  • damage to the cornea,
  • premeture aging of the skin,
  • keratoses and
  • skin cancer

The three main types of skin cancer in Australia are basal cell carcinoma, squamous cell carcinoma and melanoma.

Photosensitising Substances
Photosensitising substances will increase the effects of exposure to UV. They include:

  • industrial chemicals, such as dyes, coal tars and derivatives and chlorinated hydrocarbons.
  • drugs,
  • plants,
  • oils & fragrances and
  • sunscreen additives

A list of these substances can be found in Appendix 2 of the Worksafe Australia Guidance notes on the Protection of Workers from Ultraviolet radiation in Sunlight

Health Surveillance
In most cases, health surveillance for skin cancer involves self-screening, that is, people examining their bodies themselves. The NSW Cancer Council provides information on [||self screening]] procedures. It is important for people to regularly check all parts of the body, in particular, the areas most often exposed to the sun, that is, the ears, face, neck, shoulders, arms and hands.

If any abnormalities are detected that may indicate the presence of a skin cancer or sunspots (keratoses), a medical practitioner should be consulted promptly. This can be done through the University Health Service or your own doctor.

High risk individuals should be examined by their general practitioner every 12 months. Individuals at high risk of melanoma are those with multiple atypical naevi (moles) who have a history of melanoma in themselves or in one or more first degree relatives. Individuals who are at high risk of non melanoma skin cancer are those with a fair complexion, a tendency to burn rather than tan, have freckles, light eye colour, light or red hair colour and previous nonmelanoma skin cancer (NMSC).

However, employers may wish to provide a screening programme for those employees exposed to UV radiation, even if the exposure occurs on an intermittent or part-time basis.


Outdoor workers undertaking tasks during seasonal heat are at risk of suffering mild to serious heat-related illnesses, generaly known as heat stress.
The term Heat Stress can cause the following effects ranging from mild discomfort to serious illness:

  • Prickly heat
  • Heat cramps
  • Heat fainting
  • Heat exhaustion
  • Heat stroke

Apart from the above effects, working in seasonal heat can effect health and safety in a variety of ways, including:

  • reducing ability to concentrate
  • increasing discomfort when wearing protective clothing and using protective equipment
  • aggravating the effects of other hazards such as noise
  • aggravating pre-existing illnesses.

The human body is able to maintain a viable core temperature through a variety of physiological mechanisms. One mechanism of dissipating excess body heat is by evaporative cooling, which relies on the evaporation of sweat from the skin. The evaporation rate varies depending upon factors such as the humidity and air movement over the skin. Evaporation of sweat results in loss of fluid in the body and dehydration can occur unless fluid balance is maintained.

The risk of heat stress arises from a combination of factors including:

  • intensity of physical work
  • climatic conditions (eg. low air movement, high humidity levels and high air temperature)
  • insufficient water consumption
  • individual factors that may cause dehydration (such as poor diet, vomiting, diarrhoea or alcohol and caffeine consumption)
  • individual medical conditions that may cause heat stress (such as heart problems, diabetes or hypertension)
  • inadequate cooling off or rest periods
  • inappropriate clothing
  • individual medication that may affect the body's temperature regulation
  • an individual's age, general physical fitness and weight.


The risk of developing skin cancer from exposure to sunlight varies from person to person, depending on factors such as skin type, past exposure especially during childhood and previous history of skin cancers. However, everyone should protect their skin and eyes from prolonged exposure to solar radiation, regardless of skin type and other factors.
Similarly, individuals vary in their tolerance of hot or humid conditions, due to factors such as acclimatisation, fitness, health, physical effort required for the task and clothing being worn.

Work Organisation
In order to protect outdoor workers from the effects of UV solar radiation and heat stress, the working environment and/or working arrangements must be controlled.
The following measures should be implemented in combination to adequately protect outdoor workers from seasonal heat and UV radiation.

  • Allocation of outdoor work to certain times of day.
    During periods of seasonal heat and/or humidity, moderate and heavy outdoor work should be assigned to cooler parts of the day.
  • Provision of shade
    Outdoor work should be conducted in shaded areas as much as possible.
  • Provision of alternative tasks
    In hot and humid conditions, consideration should be given to ceasing outdoor tasks involving heavy manual work in favour of alternative moderate or light manual work.
  • Provision of rest breaks
    Outdoor workers should take hourly rest breaks in a cool place as close as possible to the place where they are working. They should not have to walk a long distance nor rest in a hot unshaded location.
  • Provision of fluids to prevent dehydration
    Workers need to take regular cool drinks when working in the heat to replace sweat lost and avoid dehydration. When working at a distance from their base, an insulated flask should be provided by the University for a handy supply of cool liquid, preferably water.

Temperature Guidelines
For outdoor work in the Sydney urban area, consideration should be given to ceasing heavy manual outdoor work when the temperature reaches 30 degrees celsius. Between 30 degrees celsius and 35 degrees celsius moderate or light manual work outdoors would generally be appropriate. Light work only would be generally appropriate at temperatures between 35 degrees celsius and 38 degrees celsius. When the temperature exceeds 38 degrees celsius, consideration should be given to ceasing all outdoor work. In this case alternative duties in cooled or indoor conditions should be assigned, but if this is not possible, it may be advisable to place workers on stand-by until conditions are more suitable.

Personal protection - Solar UV
Detailed information on on personal protection for exposure to solar ultraviolet radiation is available at the Sunsmart Sunprotection web page.
The types of personal protection are:

Control Measures - Heat Stress
It is recommended that outdoor workers:

  • Wear a hat and light sun protective clothing
  • Drink at least one litre of water per hour when working in the sun
  • Take breaks in cool shaded areas to enable a rapid return of core temperature to normal
  • Acclimatise to outdoor work gradually
  • Eat at regular intervals during the day to ensure their energy and salt levels are maintained
  • Avoid alcohol, caffine and drugs which can increase urine output and therfore fluid loss


Workplace health and safety legislation in Australia requires employers to provide and maintain, as far as is practicable, a working environment that is safe and without risks to health. This is the employer's general duty of care.
Workers are required to comply with instructions given by their employer for reasons of health and safety and take reasonable precautions to protect themselves and others at work.
Workers should report any problems in achieving compliance to their employers.


  • ACTU-VTHC Occupational Health and Safety Unit, Guidelines on Working in Heat, December 1998
  • Worksafe Australia Guidance Note for Protection of Workers from the Ultraviolet Radiation in Sunlight, November 2008
  • Sunsmart SunSmart 2012.
  • SafeWork NSW Heat stress
  • Standards Association
    - AS1067.1 - Sunglasses and fashion spectacles - safety requirements
    - AS1377 - Eye Protectors for Industrial Applications
  • Other
    - Baker, M. Surviving the Elements - Outdoor Workers' Safety, Australian Safety News, December 1993, 28-39.
    - Enander, A.E. & Hygge, S. Thermal Stress and Human Performance, Scandinavian Journal of Environment and Health, 1990 Vol 16 Suppl 1, 44-50.
    - Webb, G. Solar Radiation Protection for Outdoor Workers, Journal of Occupational Health and Safety - Australia & New Zealand, 1992, Vol 8 No 6, 479-485.