In early May 2024, Indonesia's Meteorology, Climatology and Geophysics Agency recorded temperatures above 36°C in several areas: 37.1°C in Deli Serdang, and 36.6°C each in Medan, Kapuas Hulu, Sidoarjo and Bengkulu. The agency expected 63.66 percent of season zones to enter the dry season between May and August 2024, and stressed that the conditions were not a heatwave like the one affecting parts of Asia. Under the WMO definition it cited, a heatwave is prolonged hot air for 5 or more consecutive days with daily maximum temperatures 5°C or more above average, whereas the heat in Indonesia is a yearly phenomenon driven by the apparent motion of the sun and clear daytime skies (Badan Meteorologi, Klimatologi, dan Geofisika [BMKG], 2024).
Not a heatwave does not mean harmless for workers. The question matters for any project or field operation that takes on new workers during the dry season. This case study reads an official report on work-related heat illness and death to answer one question: who is most at risk, and when?
The Cases
The report was prepared by a heat illness workgroup of the Occupational Safety and Health Administration (OSHA) with a NIOSH representative, and published by CDC. The workgroup reviewed every federal enforcement case in 2012 and 2013 that led to citations under the general duty clause of the US Occupational Safety and Health Act, since the country had no specific heat standard at the time. There were 20 cases involving 18 private employers and 2 federal agencies. In 13 cases a worker died from heat exposure, and in 7 cases two or more workers had symptoms of heat illness. Thirteen worksites were outdoors, and all the work involved was heavy or moderate. The events occurred on days with a heat index between 29.0°C and 41.0°C, while those in direct sunlight may have experienced a heat index up to 8.3°C higher (Arbury et al., 2014).
Contributing Factors
Two findings stand out. The first is timing: nine of the 13 deaths occurred within the first 3 days of work, four on the first day in a new job or after returning from time away, three on the second day and two on the third. The other four deaths were among long-time employees. The second is the prevention programme: none of the programmes was complete. Twelve employers had no programme at all, seven had inadequate water management, 13 failed to provide shaded rest areas, only one used work-rest cycles, and none had an acclimatisation programme (Arbury et al., 2014).
The report also states its limitations: information was collected retrospectively, weather data came from stations that were not necessarily close to the worksite, and some programme elements may not have been recorded by inspectors (Arbury et al., 2014).
Hierarchy of Controls
We read these findings through the hierarchy of controls. Environmental heat outdoors is hard to eliminate, so control shifts to engineering measures (shade, ventilation), administrative measures (schedules, work-rest cycles, acclimatisation) and personal protection. What stands out is that the largest failures in these cases were in cheap administrative controls. Acclimatisation is a set of physiological adaptations, such as more efficient sweating and more stable circulation, that develop after gradually increased exposure to heat (Arbury et al., 2014). New workers do not yet have them, so a schedule that treats them like experienced workers puts them at the highest risk.
Indonesia already has a legal framework. Ministry of Manpower Regulation 5/2018 on the work environment defines work climate as the combination of temperature, humidity, air movement and radiant heat with the body's heat output, sets the wet bulb globe temperature index (ISBB, or WBGT) as the parameter for assessing hot work climates, and lists WBGT threshold limit values in its annex (Ministry of Manpower of the Republic of Indonesia [Kemnaker], 2018). A literature review on construction workers likewise notes that heat illness risk rises where protective regulations are scarce or not enforced, particularly for vulnerable groups such as migrant workers (Acharya et al., 2018). The limits of the evidence should be stated: the OSHA cases come from the United States, with a different climate and different work patterns.
Lessons for Site Work
The report sets out an acclimatisation schedule that can be adopted directly (Arbury et al., 2014):
- New workers, and workers returning after more than a week away, start with 20 percent of the usual duration of work in the hot environment on day one, increasing by no more than 20 percent each day.
- During a sudden spell of excessive heat, even experienced workers start at 50 percent on day one, 60 percent on day two, 80 percent on day three and 100 percent on day four.
- Full acclimatisation may take 14 days or longer.
Beyond that, measure WBGT at the workstation rather than relying on air temperature (Kemnaker, 2018), provide drinking water and shaded rest areas, name one person responsible for the programme, and train workers and supervisors to recognise the signs of heat illness.
How Nusa Safety Helps
Nusa Safety helps companies measure heat stress at the workstation with standard instruments and methods through its Ergonomics and Work Environment Assessment, and prepares workplace first aiders with licensed partners through its First Aider (P3K) programme. Certificates issued by Nusa Safety are internal training certificates; OHS certificates and licences are issued by the competent authorities.
This article is general information and not legal or professional advice for any specific case.
References
- Acharya, P., Boggess, B., & Zhang, K. (2018). Assessing heat stress and health among construction workers in a changing climate: A review. International Journal of Environmental Research and Public Health, 15(2), 247. https://doi.org/10.3390/ijerph15020247
- Arbury, S., Jacklitsch, B., Farquah, O., Hodgson, M., Lamson, G., Martin, H., & Profitt, A. (2014). Heat illness and death among workers, United States, 2012-2013. Morbidity and Mortality Weekly Report, 63(31), 661-665. https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6331a1.htm
- Badan Meteorologi, Klimatologi, dan Geofisika. (2024, May 3). Analisis suhu panas dan potensi cuaca signifikan di sebagian wilayah Indonesia sepekan ke depan [Analysis of hot temperatures and potential significant weather in parts of Indonesia for the week ahead] [Press release]. https://www.bmkg.go.id/siaran-pers/analisis-suhu-panas-dan-potensi-cuaca-signifikan-di-sebagian-wilayah-indonesia-sepekan-ke-depan
- Ministry of Manpower of the Republic of Indonesia. (2018). Peraturan Menteri Ketenagakerjaan Nomor 5 Tahun 2018 tentang Keselamatan dan Kesehatan Kerja Lingkungan Kerja [Regulation No. 5 of 2018 on Occupational Safety and Health of the Work Environment]. https://jdih.kemnaker.go.id/peraturan/detail/1546
