University of Oulu

Wantanee Phanprasit, Kannikar Rittaprom, Sumitra Dokkem, Aronrag C. Meeyai, Vorakamol Boonyayothin, Jouni J.K. Jaakkola, Simo Näyhä, Climate Warming and Occupational Heat and Hot Environment Standards in Thailand, Safety and Health at Work, Volume 12, Issue 1, 2021, Pages 119-126, ISSN 2093-7911,

Climate warming and occupational heat and hot environment standards in Thailand

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Author: Phanprasit, Wantanee1; Rittaprom, Kannikar1; Dokkem, Sumitra2;
Organizations: 1Dept. of Occupational Health and Safety, Faculty of Public Health, Mahidol University, Bangkok, Thailand
2Aisin Takaoka Asia Co. Ltd., Bangkok, Thailand
3Dept. of Epidemiology, Faculty of Public Health, Mahidol University, Thailand
4Department of Global Health and Development, London School of Hygiene & Tropical Medicine, London, United Kingdom
5Center for Environmental and Respiratory Health Research, University of Oulu, FI-90220, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.8 MB)
Persistent link:
Language: English
Published: Elsevier, 2021
Publish Date: 2021-04-23


Background: During the period 2001 to 2016, the maximum temperatures in Thailand rose from 38–41°C to 42–44°C. The current occupational heat exposure standard of Thailand issued in 2006 is based on wet bulb globe temperature (WBGT) defined for three workload levels without a work–rest regimen. This study examined whether the present standard still protects most workers.

Methods: The sample comprised 168 heat acclimatized workers (90 in construction sites, 78 in foundries). Heart rate and auditory canal temperature were recorded continuously for 2 hours. Workplace WBGT, relative humidity, and wind velocity were monitored, and the participants’ workloads were estimated. Heat-related symptoms and signs were collected by a questionnaire.

Results: Only 55% of the participants worked in workplaces complying with the heat standard. Of them, 79% had auditory canal temperature ≤ 38.5°C, compared with only 58% in noncompliant workplaces. 18% and 43% of the workers in compliant and noncompliant workplaces, respectively, had symptoms from heat stress, the trend being similar across all workload levels. An increase of one degree (C) in WBGT was associated with a 1.85-fold increase (95% confidence interval: 1.44–2.48) in odds for having symptoms.

Conclusion: Compliance with the current occupational heat standard protects 4/5 of the workers, whereas noncompliance reduces this proportion to one half. The reasons for noncompliance include the gaps and ambiguities in the law. The law should specify work/rest schedules; outdoor work should be identified as an occupational heat hazard; and the staff should include occupational personnel to manage heat stress in establishments involving heat exposure.

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Series: Safety and health at work
ISSN: 2093-7911
ISSN-E: 2093-7997
ISSN-L: 2093-7911
Volume: 12
Issue: 1
Pages: 119 - 126
DOI: 10.1016/
Type of Publication: A1 Journal article – refereed
Field of Science: 3142 Public health care science, environmental and occupational health
Copyright information: © 2020 Occupational Safety and Health Research Institute, Published by Elsevier Korea LLC. This is an open access article under the CC BY-NC-ND license (