Prevention of heat stroke in the workplace in California

• In Hong Kong, the number of very hot days (i.e. day with maximum daily temperature of at least 33°C) almost tripled over the past decade to a record high of 54 days in 2021. Coupled with very high relative humidity in the region of 80%, the "apparent temperature" for outdoor workers could reach 45°C during very hot days.^{1Legend symbol denoting For details of measurement of apparent temperature, see Figure 1.} Heat-related stress has thus become an emerging occuaptional hazard. In the summer of 2022, half of the surveyed outdoor workers responded that they suffered from various symptoms of heat stroke recently,^{2Legend symbol denoting 綠色和平及香港天主教勞工事務委員會(2022).} whereas there were at least five reports of workplace fatalities in June and July 2022 suspected to have linkage with heat stroke.^{3Legend symbol denoting All five cases involved construction workers in their fifties or sixties. They were found unconscious on construction sites without signs of accidents. For details, see 香港01 (2022a, 2022b) and 香港財經時報(2022).}
• So far there are no dedicated statutory provisions in Hong Kong to protect local workers from heat-related illness. Neither is heat stroke added into the list of 52 compensable occupational diseases under the Employees' Compensation Ordinance ("ECO"), nor is there any specific requirement laid down in the Occupation Safety and Health Ordinance ("OSHO") to prevent incidence of heat stroke. In 2009, the Labour Department ("LD") advised employers to provide rest breaks and shade to manual workers during hot days in the "Risk Assessment for the Prevention of Heat Stroke at Work", but it is voluntary guidelines rather than a legal requirement. There is thus increased advocacy of enhanced protection against heat stroke, such as making it a compensable occupational disease and mandatorily requiring employers to roll out preventive measures. Between 2017 and 2022, the subject of heat stroke in the workplace was discussed at the Legislative Council ("LegCo") on at least six occasions.^{4Legend symbol denoting GovHK (2018, 2022) and Legislative Council Secretariat (2022).}
• Globally, more places (e.g. the Mainland, a few European countries and a number of states in the United States ("US")) have enacted dedicated legislation to prevent heat stroke in the workplace over the past three decades. Amongst the advanced places, California State in the US is one of the first to enact such a law in 2006, which is acclaimed by the International Labour Organization ("ILO") as a good practice to protect outdoor workers.^{5Legend symbol denoting International Labour Organization (2019).} This issue of Essentials presents policy developments on workplace heat stroke prevention in California, after a review of the recent situation in Hong Kong.

• Apparent temperature as the key indicator of risk for heat stroke: If a person cannot cool down through sweating to maintain normal body temperature of 37°C, the person may suffer from heat stroke and relevant symptoms may be observed. As perspiration capability depends critically on relative humidity, air temperature on a standalone basis cannot fully reflect the heat-related health risks.^{6Legend symbol denoting World Health Organization (2018) and Ebi et al. (2021).} Some overseas observatories thus include apparent temperature in their daily weather forecast, taking into account the humidity factor. Taking the US model as an illustration, given the air temperature of 33°C, the apparent temperature under the scenario of low humidity of 50% is 36°C, but this will rise to 48°C under a high humidity scenario of 80% (Figure 1).
  Figure 1 – Apparent temperature and risks of heat stroke⁽¹⁾
  
  Note: (1)Figures in the table refer to measurements in shady locations. Exposure to full sunshine can increase apparent temperature further by up to 8°C.
  Source: The United States National Weather Service.
• Heat stroke as an occupational hazard: Based on scientific research results, when the said apparent temperature reaches 33°C (i.e. extreme caution zone), heat-related symptoms of cramps, dizziness and nausea may occur due to heavy sweating and dehydration. When apparent temperature exceeds 40°C (i.e. danger zone), workers become more likely to suffer a heat stroke, a more serious condition which leads to risks of mental confusion, seizures, loss of consciousness, organ damage or even death. Extreme heat will also aggravate existing conditions (e.g. respiratory and cardiovascular diseases) of the victims.^{7Legend symbol denoting International Labour Organization (2019).} Moreover, heat magnifies the probability of work accidents (e.g. falling from heights) caused by dizziness, sweaty palms or fogged-up glasses. Based on global studies, one-third of workers exposed to extreme heat end up with different degrees of heat-related illness in recent years.^{8Legend symbol denoting Ebi et al. (2021).}
• Preventive measures around the globe: In face of looming challenges arising from climate change, some advanced places (e.g. four states in the US and at least six European countries) have enacted laws and regulations to mandate employers to prevent heat stroke in the workplace.^{9Legend symbol denoting The four states in the US are California, Minnesota, Oregon and Washington. The six European countries are Belgium, Hungary, Latvia, Montenegro, Slovenia and Spain. See European Trade Union Confederation (2022).} For the Mainland, it also released the "Administrative Measures on Heat Stroke Prevention" in 2012, mandating employers to (a) provide heat allowances when outdoor air temperature reaches 35°C or indoor apparent temperature reaches 33°C at a daily rate of RMB5 (HK$6) to RMB25 (HK$30);^{10Legend symbol denoting The amount of heat allowance and applicable period vary across provinces. See 騰訊網(2022).} (b) cut short daily outdoor work to six hours when temperature reaches 37°C; and (c) stop outdoor work entirely when temperature reaches 40°C.^{11Legend symbol denoting Temperature limits for outdoor work refer to the daily maximum air temperature predicted by the local observatory, while that for indoor work refers to wet-bulb globe temperature (i.e. a measure of apparent temperature taking humidity, radiation and wind into consideration) measured at workplace. See 國家衞生健康委員會(2012).} Employers are also required by law to offer free cool drinks, rest areas and safety training on heat-related illness to their employees.

• Sizzling temperature in summer: The adverse impact of global warming is increasingly felt in Hong Kong, with its number of very hot days almost tripling from 19 days in 2011 to a record high of 54 days in 2021 (Figure 2). As discussed above, the apparent temperature under very humid weather could breach the 45°C level in very hot days.
  Figure 2 – Number of very hot days ⁽¹⁾ and heat-related workplace inspections
  
  Note: (1)Days with maximum daily temperature of at least 33°C.
  Sources: Hong Kong Observatory (2022) and Labour Department (various years).
• Affected workforce: Prima facie, outdoor workforce (e.g. construction site workers, cleaners, security guards and horticultural workers) exposed to sunlight is most prone to the risks of heat stroke. More recently, public concerns over heat-related risks spread to indoor workforce in hot work environments (e.g. kitchens, spaces for elevator repairs and container terminals) as well.
• Incidence of heat-related illness: Based on the statistics on occupational injuries kept by LD, the number of heat-related injuries averaged at just 22 cases per annum from 2017 to 2021, with one fatal case recorded in 2018. Yet local concern groups dismiss such statistics as unreliable. Reportedly many cases of heat-induced illness have not been counted as occupational injuries, either because there were no obvious signs of work accidents, or because they were attributed to pre-existing conditions (although they might be induced by heat). Based on a survey of selected outdoor workers with a very limited sample size released by concern groups in September 2022, 53% of outdoor cleaners reported symptoms of heat stroke in the most recent two months.^{12Legend symbol denoting 綠色和平及香港天主教勞工事務委員會(2022).} In June-July 2022, at least five deaths in the workplace were reportedly suspected to be related to heat stroke.^{13Legend symbol denoting See Endnote 3.}
• Alleged limitations of existing ordinances: Under OSHO, employers need to make sure that their workplace is free of "hazards" in general terms. Arguably, it could cover "extreme heat", but OSHO stops short of laying down detailed work arrangements to protect workers from heat stroke apart from provision of drinking water. Under ECO, workers may get compensation for heat-induced illness (e.g. heat stroke), but only if the illness is proven to be an injury caused by a work accident. For heat-related illness not proven to be related to work accidents, it is not categorized as statutory occupational diseases, and hence, the victims are not eligible for compensation. LD reiterates that the existing classification of occupational diseases is based on criteria recommended by ILO, with (a) "definite causal relationship" with specific work hazards, and (b) "significantly higher" risk for workers concerned as key determinants.^{14Legend symbol denoting Labour Department (2022).}
• Recent administrative measures: In 2009, LD introduced guidelines on "Risk Assessment for the Prevention of Heat Stroke at Work", advising employers to roll out preventive measures when risk factors (e.g. air temperature of 32°C and relative humidity of 85%) emerge. These measures include (a) offering rest breaks after 20-40 minutes of work; (b) rescheduling work to cooler hours before 10:00 a.m. or after 4:00 p.m.; and (c) putting on appropriate clothing.
  LD also conducts 20 000-30 000 inspections of high-risk workplaces (mostly construction sites) annually. Between 2011 and 2021, the annual number of warnings issued to employers plunged by 97% from 437 to 14, along with a visible fall in the number of prosecutions from seven to two. LD attributed this to the fact that "most employers and contractors had…taken appropriate preventive measures" on the back of increased publicity and inspections.^{15Legend symbol denoting Ibid.} Moreover, LD promotes usage of cooling gears, sponsoring small to medium-sized enterprises to buy 21 400 portable waist fans for delivery to workers as of 2021.
• Issues of concern: Local concerns groups cast doubt on the effectiveness of the above measures, however. First, the number of pertinent prosecutions citing OSHO is just a handful each year recently, suggesting limited enforceability of the guidelines.^{16Legend symbol denoting 明報(2022), 綠色和平及香港天主教勞工事務委員會(2022) and 香港財經時報(2020).} Secondly, the guidelines do not specify extra requirements for preventive measures if air temperature rises above 32°C. Thirdly, allegedly heat stroke in the workplace without visible injuries arising from accidents is often not compensable under ECO. There are thus calls in the community to offer better protection to the local workforce from extreme heat with clearer reference to air or apparent temperature, and some go further to suggest making such measures mandatory.
  In reply to a LegCo question in July 2022, the Government reiterated that "it is not appropriate to regulate outdoor working hours and rest periods based solely on temperature".^{17Legend symbol denoting GovHK (2022).} Instead, it is prepared to formulate "more detailed and specific" guidelines for release in April 2023, based on Hong Kong Heat Index (which factors in air temperate, humidity, wind and solar radiation) developed by the Hong Kong Observatory.^{18Legend symbol denoting 香港電台(2022).}

• The temperature in the state of California in summer is not particularly high, averaging at 23°C only, ranking 17th amongst the 50 states in the US. That said, some cities (e.g. Los Angeles, Sacramento and San Jose) within the state are prone to extreme heat, with air temperatures exceeding 40°C in some summer days, posing health risks to at least 1.34 million outdoor workforce pre-dominantly in farms and construction sites. Before 2005, the Occupational Safety and Health Act in California was very general and did not have specific measures to protect workers from heat stroke.
• Enactment of "Heat Illness Prevention in Outdoor Places of Employment" in 2006: While heat-related illness in the workplace began to attract much public attention in California in the 1990s, the tragedy of 13 heat-induced workplace deaths in 2005 was a catalyst for change.^{19Legend symbol denoting California Legislative Information (undated) and EHS Today (2006).} In August 2005, the then-Governor Arnold Schwarzenegger issued emergency orders to mandate employers to offer water and shade to their outdoor employees. In July 2006, these orders were adopted by the Occupational Safety and Health Standards Board as permanent regulations (i.e. "Heat Illness Prevention in Outdoor Places of Employment", or "the Regulations"). In November 2010 and May 2015, the Regulations were revised to offer further protection, especially for high-risk industries (e.g. agriculture and construction).^{20Legend symbol denoting Natural Resources Defense Council (2022).} On this basis, the California government issued "Employer Sample Procedures for Heat Illness Prevention" in May 2015 to provide elaborate guidelines on compliance with the Regulations.
• Major protection measures against heat-illness in California: As suggested by the name, the Regulations aim at protecting outdoor workers (e.g. workers engaged in agriculture, construction, landscaping, oil and gas extraction and transportation) only. Moreover, the Regulations set two temperature thresholds (26.7˚C and 35˚C) for more stringent requirements on employers. The salient features of the Regulations and related measures are set out below:
  • (a)
    Mandatory provision of shade: Regardless of temperature, shade should be available for timely access upon employees' requests. Employees should also be encouraged to take a cool-down rest in the shade for at least five minutes whenever needed. If air temperature reaches 26.7˚C, provision of a shade by employers becomes a statutory requirement, and the shade must be large enough to accommodate all outdoor employees in rest breaks to sit together without physical contact amongst themselves;
  • (b)
    Mandatory rest periods: Workers are entitled to a rest break no shorter than five minutes whenever workers feel the need to recover from overheating, regardless of temperature. If air temperature reaches 35°C or above, farm workers must be provided with a ten-minute break once every two hours;
  • (c)
    Mandatory provision of drinking water: Employers are required to provide fresh, pure, suitably cool and easily accessible drinking water of at least one quart (946 ml) per hour per outdoor worker. If the daytime temperature is expected to exceed 26.7˚C, employers are further required to hold safety meetings to brief workers on the importance of frequent drinking of water;
  • (d)
    Assignment of a safety supervisor to monitor heat-related illness: Employers must designate a supervisor to closely monitor employees when (i) the predicted maximum temperature reaches 26.7°C and is 5.6°C higher than the average figure in the past five days; or (ii) the workers are newly assigned to a high heat area in the first two weeks of their work.

    If temperature reaches 35°C, additional preventive measures are imposed on employers in the high-risk industries (e.g. agriculture). For example, each supervisor can only monitor at most 20 workers so that physical conditions of every worker are duly monitored;
  • (e)
    Mandatory heat-related illness prevention plan: Employers must formulate a "heat-related illness prevention plan" and make it available to all workers. On top of the above measures, the plan should provide necessary training to relevant employees and have emergency response procedures; and
  • (f)
    Compensation to employees for heat-related illness: Under California workers compensation rules revised in 2002, occupational injuries include illness caused or aggravated by any event or exposure "occurring in the work environment".^{21Legend symbol denoting California Code of Regulations, Title 8, Section 14300.5.} As such, heat exhaustion and heat stroke are listed as compensable in the state, with an annual average of 939 heat-related claims recorded from 2010 to 2020.^{22Legend symbol denoting Division of Workers' Compensation (2022).}
• To date, California is still trying to improve its regulations on heat stroke prevention. For outdoor workers, California will revise the Regulations so that every worker can have a copy of the heat-related illness prevention plan, with additional measures to help workers adapt to "ultra-high" temperature.^{23Legend symbol denoting The original bill contained more concrete suggestions such as increasing health monitoring and rest breaks when the temperature reaches 40.6˚C. They were removed from the final version reportedly due to opposition from employer associations. See California Legislative Information (2022) and Fox40 (2022).} Turning to indoor workers, which are not covered by the Regulations, the California government has been drafting the corresponding heat protection regulations since 2017. Yet, these have not been finalized after several drafts due to diverse views in the community. Some employers raised objections repeatedly because they thought that some proposed measures are "unnecessarily burdensome".^{24Legend symbol denoting Fisher Philips (2017) and California Chamber of Commerce (2019).} At this juncture, it is not clear when the regulations for indoor workers can be implemented in California.
• Policy effectiveness: California is the first state in the US to have offered statutory protection to outdoor workforce from heat-related illness and it seems to have effectively reduced the incidence of such illness. Based on an empirical study completed in 2021, the annual average number of occupational injuries caused by hot weather plunged by 30.3% from 6 100 during the period from 2001 to 2005 to 4 250 during 2006 to 2018.^{25Legend symbol denoting Park et al. (2021).} Reportedly, the US federal government is now initiating a plan to make similar heat-related illness rules for outdoor workers across all 50 states.