Every summer, workers - particularly those in agriculture, landscaping and construction - spend long days working in the hot sun. And every year, without fail, many die or become ill due to heat exposure.

Heat can cause a variety of disorders whose consequences can range from minor discomfort to death. They include skin lesions, oedema, syncope, cramps, exhaustion, and, the most severe of all, heat stroke. Signs of heat-related disorders comprise excessive sweating, weakness in the limbs, disorientation, headaches, dizziness and, in extreme cases, loss of consciousness and also loss of the ability to sweat. The latter symptoms are life-threatening and immediate action is required.

Management precautions that help to prevent heat stress include the provision of canopies or awnings on the site to shield workers from direct exposure to solar radiation; the scheduling of appropriate breaks and the provision of air-conditioned sheds or vehicles for rest breaks. Workers should also be provided with drinking water in sufficient quantity and encouraged to drink frequently by positioning the water supply near working places.

Workers should be informed of the nature of heat stress and its adverse effects as well as of precautions to be taken and of measures to be provided by the management. They should be advised of the importance of drinking sufficent quantities of liquid and eating a balanced diet. It is often recommended that persons drink 1 litre per hour of work in the sun or in high temperatures. In addition, workers should be trained to recognize the symptoms of heat disorders and to learn the basics of first aid and where to call for help when they recognize these signs in themselves or in others.

CIS offers below a list of selected resources that can be consulted online by everyone concerned with the protection of workers to assess heat-related hazards and to recognize and treat the associated disorders. It includes information on preventive measures as well as details on physiological responses to heat stress.

ILO Resources

• ILO Encyclopaedia on Occupational Safety and Health, chapter Heat and Cold, International Labour Office, Geneva 1998.
  Description: Collection of articles focusing on the physiological basis of thermoregulation, on effects and assessment of heat stress as well as on preventive strategies :
  • Physiological Responses to the Thermal Environment
  • Effects of Heat Stress and Work in the Heat
  • Heat Disorders
  • Prevention of Heat Stress
  • The Physical Basis of Work in Heat
  • Assessment of Heat Stress and Heat Stress Indices
  • Heat Exchange Through Heat Stress
  
  
• ILO Code of Practice on Ambient factors in the workplace, see section 8 (pp. 42-48), International Labour Office, Geneva, 2001.
  Description: This code of practice provides recommendations and guidelines for assessing, eliminating and controlling hazardous ambient factors in the workplace by reviewing the various aspects of prevention and control of each ambient factor, including heat and providing guidance on hazard assessment and prevention, surveillance of workers' health and workers' information and training.

Resources issued by CIS National and Collaborating Centers

• Keep Your Top on: Health Risks from Working in the Sun, Health and Safety Executive (HSE), United Kingdom, 2001.
  Description: Leaflet giving advice to outdoor workers on health risks from working in the sun.
   
• Dossier web: Travailler par de fortes chaleurs en été [Topic: Work During Summer Hot Spells], Institut national de recherche et de sécurité (INRS), France.
  Description: Web site proposing solutions to problems arising during hot spells to protect workers; it also recalls the French legislation requirements.
   
• Safety in the Hot Summer Sun, Canadian Centre for Occupational Health and Safety (CCOHS), Ontario, Canada.
  Description: News item providing guidance on how to protect workers from sun and heat related illness.
   
• Prévention des coups de chaleur [Prevention of Heat Stress], Commission de la santé et de la sécurité du travail (CSST), Quebec, Canada.
  Description: Web page giving access to a collection of guides and tools to prevent heat stress.
   
• Chaleur et ozone [Heat and Ozone], Swiss Accident Insurance Fund (Suva), Switzerland.
  Description: Leaflets and check lists advising on how to protect workers against high temperatures and solar rays are available on this web page.
   
• Heat Stress, National Institute for Occupational Safety and Health (NIOSH), United States.
  Description: Links providing acess to information on heat-induced occupational illnesses, injuries, and reduced productivity, as well as methods that can be taken to reduce risk.

Other resources

• OSHA Fact Sheet: Working Outoors in Warm Climates, Occupational Safety and Health Administration (OSHA), U.S. Department of Labor, 2005.
  Description: Fact sheet providing guidance on how to protect outdoor workers against heat and sun exposure.
   
• Fact Sheet: Working in Hot Temperatures, Workers Health Centre, Australia, 2004.
  Description: Data sheet overviewing symptoms of heat disorders and strategies to prevent them.
   
• Heat Stress - Guidelines for Recognition, Assessment and Control in Construction, Construction Safety Association of Ontario, Canada, 2000.
  Description: Guidelines for recognizing, assessing and controlling heat stress; construction operations where heat stress commonly occurs; workplace responsibilities; policies and procedures; preventative measures; first aid treatments.
   
• Ambiances thermiques: travail en période de fortes chaleurs [Thermal Environments: Work During Hot Spells], Documents pour le médecin du travail, France, 2004
  Description: Information and guidance on health effects of work in hot environments and possible preventive measures.
   
• Travailler dans un contexte de forte chaleur [Working in a Context of High Heat], Agence nationale pour l'amélioration des conditions de travail (ANACT), France.
  Description: Web page determining workers rights and possible actions when working in a hot environment.
   
• Travail à la chaleur [Work in Heat], Fiche de risque no 18, Bossons Futé, France
  Description: Index of risks and possible preventive actions when working in heat.