Indicators of occupational heat hazards due to climate change

Introduction:  The impacts on occupational health and productivity when people are forced into heavy physical labour in hot environments are well established. Low income workers in tropical countries may be worst affected. It is likely to get worse due to increasing heat related to climate change. 30+ heat stress indexes were published since 1950.  New ones are emerging. This makes it difficult to compare or integrate findings on occupational heat stress in different countries.      

Methods:  We compared calculated heat stress indexes and reviewed the literature on heat stress impacts, as well as analysed their application in climate change impact assessments. A Delphi method with key experts globally was applied to produce a proposed International Guideline for indicators of occupational heat hazards. The aim is to have this discussed and approved at ICOH.    

Results:  The wide application of WBGT in international and national standards and recommendations for heat hazard protection makes this a starting point. The new UTCI, promoted by WMO, is another global candidate for a recommended indicator. Other models that calculate core body temperature and sweat rate under specified conditions have also been assessed.    

Discussion:  The final recommendations will be completed in a series of meetings during 2011, and discussion will take place in a symposium on heat indicators during the ICOH conference.