OUTDOOR WORKERS EXPOSED TO ULTRAVIOLET RADIATION & SEASONAL HEAT

Note: This document is a working document which has not yet received final approval. Please forward any comments you may have concerning this document to Leanne Mumford in the Risk Management Office, K07, email: .

Policy

1. Who are these Guidelines for?
2. Hazards of Outdoor Work
   2.1 Natural Ultraviolet Radiation
   2.2 Seasonal Heat
3. Recommendations for Work Organisation and Personal Protection
   3.1 General
   3.2 Work Organisation
   3.3 Personal Protection
4. References

Policy

Outdoor work at any time of the year can expose staff to solar ultraviolet radiation, which can cause skin and eye effects such as sunburn, skin cancers and cataracts. In seasonally hot conditions outdoor work can pose the additional hazard of heat stress.

The University is committed to ensuring that staff and students work in healthy and safe conditions. For outdoor work this means that the University is committed to organising work to control exposure to solar radiation and heat stress hazards, and to providing personal protection to minimise the effects of these hazards.

1. WHO ARE THESE GUIDELINES FOR ?

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 one of our staff, telephone 9351 4335.

2. HAZARDS OF OUTDOOR WORK

2.1 NATURAL ULTRAVIOLET RADIATION

Excessive exposure to ultraviolet radiation from sunlight can cause damage to the skin and eyes. All skin types can be affected. The level of exposure a person receives can depend upon environmental factors such as season of the year, time of day, cloud cover, and extent of shade and reflection. Clothing, hats, sunscreens and sunglasses also have an affect on level of exposure. In Australia the intensity of the sun at any time of the year in any part of the country can be enough to cause skin cancer.

In the work environment, the amount of exposure to sunlight depends upon time spent outdoors, time of day when tasks are performed outdoors, amount of shade provided to the work area, presence of reflective surfaces in the work area and use of photosensitising chemicals.

Solar radiation is most intense between 10 am and 2 pm Standard Time and between 11 am and 3 pm Daylight Saving Time. It is most intense in the summer, but sufficient exposure to be harmful can occur in the winter months and on cloudy days. Intensity increases with height above sea level and proximity to the equator.

The Ultraviolet radiation range from the sun is usually divided into 4 sets of wavelengths. The short wavelengths of vacuum UV and UV-C (between 100 nm and 280 nm) do not reach the earth. UV-B (280 nm-315 nm) causes more skin damage than UV-A (315 - 400 nm). Broad spectrum sunscreens protect against UV-B and at least part of UV-A ranges.

(a) Short term exposure effects
Short term exposure to the sun can result in sunburn. Untanned skin will show mild sunburn within 12 minutes when exposed to summer sunlight between 11 am and 3 pm daylight saving time. Permanent damage will occur after two hours of exposure.

(b) Long term exposure effects:

• Prolonged or repeated exposure to the sun can result in keratoses, skin cancers, premature skin aging and eye damage.
• Eye damage includes photoconjunctivitis and photokeratitis after prolonged exposure, and cataracts and pterygia after repeated exposure. Photoconjunctivitis is inflammation of the membrane around the eye. Photokeratitis is inflammation of the cornea. Cataracts are opacities of the lens of the eye. Pterygia are growths of tissue on the outside of the eye which can grow over the cornea.
• Keratoses are dry rough spots on the skin, and indicate prolonged exposure to UV radiation. Very occasionally these develop into skin cancers. There are three main types of skin cancers - Basal Cell Carcinoma, Squamous Cell Carcinoma and Melanoma.
• 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.
• 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.
• 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.
• Factors which place people at increased risk of developing skin cancers include childhood exposure, participation in outdoor activities for both work and leisure, living in Australia's North - Queensland, Northern Territory and northern Western Australia - and previous skin cancers.
• For information on self-screening for skin cancers, contact the NSW Cancer Council, the University Health Service or your own doctor.

(c) Photosensitising substances
Exposure to photosensitising substances can worsen the effects of exposure to the sun. These substances include drugs, plants, oils, fragrances, sunscreen additives and industrial chemicals such as dyes, coal tars and derivatives and chlorinated hydrocarbons. A list published by Worksafe Australia is available from the Risk Management Office.


2.2 SEASONAL HEAT

The risk of heat stress arises from a combination of human physical effort, which increases body temperature, and the ability of the body to shed the excess heat in order to maintain a viable core body temperature. Heat loss from the body depends on environmental factors such as radiant heat, air temperature, relative humidity and air movement. It also depends on personal factors such as intensity of physical work, acclimatisation, fitness and state of health, and clothing being worn. Even at rest, the body produces some heat. Heat loss can occur through conduction, radiation, convection and evaporation of sweat. This last mechanism is the most important in hot conditions.

Apart from the possibilities of heat stress or heat stroke, which are very rare in industry, working in seasonal heat can effect health and safety in a variety of ways. These include by:

• 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.

Dehydration can occur unless fluid balance is maintained.

3. RECOMMENDATIONS FOR WORK ORGANISATION AND PERSONAL PROTECTION

3.1 GENERAL

Individuals vary in skin type, past exposure to solar radiation and other factors, so the risk of skin cancer varies. 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 and health, physical effort required for the task and clothing being worn. Subjective feelings of heat discomfort are valid and should be taken into account.

The human body is able to maintain a viable core temperature through a variety of physiological mechanisms. Even when at rest, the body generates heat. When performing work, more heat is generated. This excess heat is lost by radiation, convection and evaporative cooling. In hot conditions it is more difficult for the body to shed heat because the surrounding air is already warm. Evaporative cooling relies on the evaporation of sweat from the skin. In humid conditions (which often prevail in Sydney) the air already contains water vapour, and evaporation of sweat into the air is reduced. Convection and evaporative cooling are assisted by air movement over the skin. Evaporation of sweat results in loss of fluid in the body. To avoid dehydration, this needs to be replenished.

The following measures should be implemented in combination; no single measure will usually be sufficient to adequately protect outdoor workers from seasonal heat and UV radiation.


3.2 WORK ORGANISATION

(a) Allocation of outdoor work to certain times of day.
Throughout the year, outdoor work should be organised as much as possible to be done outside the hours of maximum sun intensity, ie before 10 am and after 2 pm, eastern standard time, and before 11 am and after 3 pm, daylight saving time. During periods of seasonal heat and/or humidity, to reduce the risk of heat stress, moderate and heavy outdoor work should be assigned to the cooler parts of the day whenever feasible. Work involving the use of machinery should also be assigned to the cooler parts of the day whenever feasible as hot conditions can reduce concentration. Assigning these tasks to early mornings will probably be the most practical option in many cases. Supervisors should actively plan outdoor work to conform with these guidelines as far as possible.

(b) Provision of shade
Outdoor work tasks should be shaded as much as possible. Use should be made of natural shade from trees, buildings and other structures. Shade can also be created using canopies, tents and other portable, easily erected shade structures. Vehicles and machinery such as tractors and mowers may be able to be fitted with shade canopies.

Ordinary glass prevents transmission of Ultraviolet B radiation and therefore provides protection against skin cancer. Cars and trucks that are frequently or continuously used by an individual or group of staff should therefore be provided with air-conditioning systems so that they can comfortably be driven with windows closed throughout the year. For the same reason, tractors and other farm machinery in frequent use should have air-conditioned cabs.

(c) Provision of alternative tasks
Because physical work can generate additional heat which the body may not be able to lose in hot and humid conditions, alternative tasks should be available when heavy or moderate manual work is not advisable. Consideration should be given to ceasing "heavy" manual outdoor work when the temperature reaches an agreed level, and only "moderate" or "light" manual work outdoors should be performed above this temperature. Above a higher agreed temperature "light" work only would be advisable until the temperature falls. At even higher temperatures 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.

For the purposes of this document, "heavy" work refers to tasks which require continuous intense effort such as continuous shovelling; "moderate" work refers to tasks which require less intense or less continuous effort such as mowing and intermittent digging; "light" work refers to tasks which require minimum additional effort to walking such as moving hoses around.

The temperature levels at which heavy, moderate and light work cease to be advisable should be agreed at a local level by discussion between staff and supervisors, taking into account local conditions, acclimatisation of staff and tasks to be performed. Where tasks cannot be reorganised to take account of hot and/or humid conditions, provisions for adequate rest breaks and fluids become particularly important.

Although humidity is a factor in heat discomfort, ordinary dry-bulb thermometer readings are usually acceptable for general heat monitoring purposes.

(d) Provision of rest breaks
The recommended rest break period per hour for average workers performing moderate manual work in hot weather is 10 minutes. For fit, experienced workers who are keeping up their fluid intake, 5 minutes rest in every hour when doing moderate work is often adequate. However, if for any reason fitness is reduced (eg, if they have a virus infection), workers should go back to 10 minutes rest per hour until they feel comfortable taking less. New or inexperienced workers should be permitted to take at least a 10 minute rest break per hour when doing moderate work in hot weather until such time as they subjectively feel comfortable taking a shorter break.

Length of time needed for rest breaks also depends on two other factors which affect the speed at which a worker can cool down after working in the heat:

• if rest breaks can be taken in a cooled or air-conditioned building, shorter rest breaks may be adequate.
• when workers use sunscreens, the speed at which they can cool down is reduced due to decreased evaporation of sweat and longer rest breaks may be needed.

Outdoor workers should be permitted to take their hourly rest breaks in a cool place as close as possible to the place where they are working. If they are working some distance from their base, they should be permitted to go inside the closest cool building (air conditioned building if possible) or shaded area to take a rest and have cool drinks. They should not have to walk a long distance nor rest in a hot, unshaded location.

SHORT work periods followed by SHORT rest breaks are better than long work periods followed by long rest breaks.

(e) 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, they should take an insulated flask (provided by the University) for a handy supply of cool liquid, preferably water. Also, cool water dispensers should be provided in appropriate locations.

(f) Temperature guidelines for outdoor work in the Sydney area
For outdoor work in the Sydney urban area, consideration should be given to ceasing heavy manual outdoor work when the temperature reaches 30oC. Between 30oC and 35oC moderate or light manual work outdoors would generally be appropriate. Light work only would be generally appropriate at temperatures between 35oC and 38oC. While the temperature is 38oC and above, 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.


3.3 PERSONAL PROTECTION

Sunscreen creams, sunglasses and hats which have been approved by the Central Occupational Health and Safety Committee, are available from the Supply Department.

(a) Clothing
Recommended clothing for protection of the skin from UV light is loose-fitting and allows sweat to evaporate. Closely-woven fabrics of light colours are recommended. Cotton is the best fabric. Long-sleeve shirts and long trousers give good skin protection. The remaining exposed parts of the body should be protected by other means.

(b) Hats
The recommended hat has an all-round brim at least 10 cm wide, and is made of natural fibres in a light colour, for example a white "sailing" hat or wide-brimmed "giggle" hat. The hat fabric should be of a close weave to ensure it is opaque to sunlight.

(c) Sunscreens
The recommended sunscreen cream is a broad spectrum, waterproof type with a high sun protection factor (15+), such as ICI UV Ultrablock or equivalent. The recommended sunscreen has a cinnamate ester as its active ingredient. However, some individuals may be sensitive or photosensitive to some sunscreen cream ingredients, so the one cream may not be suited to all staff, and alternatives should be provided where necessary.

For maximum effectiveness, sunscreens should be applied to clean dry skin 15 minutes before going out into the sun. They should be wiped on rather than rubbed into the skin, and they should be reapplied at least every 2 hours. When profuse sweating occurs, sunscreen creams may need to be reapplied more often. Lip protection is also important so a SPF 15+ sunscreen should be regularly applied to the lips.

(d) Sunglasses
The recommended sunglasses protect against UV light penetration at the front and sides of the face and also give impact protection. They are really safety glasses with UV protection and tinting to reduce glare. These safety glasses are also available without tinting for indoor use. Safety glasses should meet the requirements of Australian Standard 1337.

Ordinary sunglasses may also be used where impact or dust protection is not required. These should conform to the requirements of Australian Standard 1067.1.

4. REFERENCES

• ACTU-VTHC Occupational Health and Safety Unit
  - Guidelines on Working in Heat, Health and Safety Bulletin No. 15, June 1982
  - ACTU Health & Safety Policy: Working in Heat, Health and Safety Bulletin No. 28, June 1983
  - ACTU Occupational Health and Safety Standard - Prevention of Occupational Skin Cancer and other Ultraviolet Radiation Hazards: Outdoor Workers Health and Safety Bulletin No. 61, June 1989
  - Working in Heat Guideline Part 1: Seasonal Heat, Health and Safety Bulletin No. 64, December 1989
  - Working in Heat Guideline Part 2: Heat Stress Areas, Health and Safety Bulletin No. 65, December 1989
• VTHC Occupational Health and Safety Unit
  - Working in Seasonal Heat, Health and Safety Bulletin No. 70, July 1991
• WorkCover Authority, Division of Occupational Health
  - Heat and Comfort in the Factory and Office, December 1989
• Worksafe Australia
  - Guidance Note for Protection of Workers from the Ultraviolet Radiation in Sunlight, October 1991
  - Protection from Sunlight, June 1992
• 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.

Page maintained by: Leanne Mumford
Last updated: 23/12/04