Extreme heat stands out as a recurring climate hazard that is both intensifying and becoming harder to predict. This year, record-shattering heatwaves have swept across Europe, Asia, and North America, leaving workers susceptible to severe heat stress for longer periods than in the past.
International human rights organizations, such as Amnesty International, view extreme heat as a multiplier of human rights harm. Left unaddressed, these conditions directly violate the fundamental rights to life, health, safe working conditions, and an adequate standard of living.
Mounting human toll
The International Labour Organization (ILO) recognizes a safe and healthy working environment as a fundamental right at work. Yet, extreme temperatures turn daily labor into a serious health hazard, contributing to roughly 489,000 heat-related deaths globally each year. This year alone, early-summer heatwaves drove thousands of excess deaths across Europe and pushed North African temperatures toward 122°F (50°C).
Beyond direct health crises, extreme heat erodes daily livelihoods. For example, in Bangladesh, extreme heat costs the economy an estimated 250 million lost workdays annually as extreme temperatures make outdoor labor unsafe or impossible during peak hours. It’s not only outdoor labor that is affected. Workers in indoor workplaces that lack ventilation, or workers who work extensively with heat-producing machinery, feel the impacts too. In Dhaka, nearly three quarters of informal workers (74%) said rising temperatures were directly eroding their health and income, forcing them to choose between risking heat-related illness or losing vital earnings.
Even in advanced economies, the risks remain high. Between April and September 2025 in the United Kingdom (UK), 44% of construction workers suffered heat-related illness onsite, and 67% cited severe concerns over a lack of basic safeguards like shaded rest, shift work, adequate protection, and hydration.
Workers most exposed
High temperatures affect workplaces year round. In poorly ventilated facilities and manufacturing hubs, heavy machinery generates intense indoor heat every day, a baseline hazard that climate-driven outdoor heatwaves exacerbate.
While entire supply chains are impacted, specific workplace conditions severely heighten risk for those with the least power to protect themselves:
- Migrant workers who can’t refuse: Migrant workers often face language barriers, tied visa status, or fear of deportation, leaving them vulnerable and unable to refuse hazardous work conditions or report safety violations during extreme heatwaves. They may also not be well versed in the company’s health and safety policies and procedures.
- No right to rest: In forced labor or highly exploitative contractual environments (such as agricultural harvesting, brick kilns, construction, and apparel manufacturing), workers can't simply stop, move into shade, or reach clean drinking water when their bodies need to as they can risk management repercussions by doing so.
- No safety net in informal work: Workers without formal contracts lack occupational safety and health (OSH) protections, medical coverage, or legal recourse, forcing them to perform heavy labor during dangerous temperature spikes.
- Indoor heat traps: In poorly ventilated manufacturing plants, processing facilities, and warehouses, indoor workers face severe heat exhaustion without access to active cooling or passive ventilation safeguards.
- Commercial decisions: Pricing demands, production targets, and tight delivery schedules push suppliers to keep output up through hot conditions, and workers bear the consequences.
The duty to act
Protecting vulnerable workers from heat-driven harm extends past short-term emergency response into a human rights duty. That duty is increasingly reflected in global regulations. From 2029, the European Union (EU) Corporate Sustainability Due Diligence Directive (CSDDD) will mandate that qualifying companies identify, prevent, and mitigate human rights risks across operations and supply chains, with OSH explicitly in scope.
As extreme temperatures become more frequent and intense, organizations cannot afford to overlook the human rights implications in their risk management and business continuity planning. Integrating heat-related risks into due diligence processes is becoming an important part of protecting people from foreseeable harm.
To translate that commitment into practice, organizations should:
- Build extreme-heat risk into supplier due diligence and risk assessments, prioritizing the regions, sectors, and worker populations most exposed to dangerous temperatures.
- Mandate site-level safeguards across operations and supply chains, including shaded rest areas, access to clean drinking water, adjusted working hours during peak heat, and real-time thermal monitoring.
- Adjust production quotas and lead times during severe heat events so suppliers are not incentivized to compromise worker safety or deny rest breaks to meet deadlines.
- Empower workers with clear, retaliation-free grievance channels and uphold ethical recruitment practices so individuals can safely report hazardous heat conditions or refuse dangerous work without fear.
Extreme heat has permanently changed the conditions of work. It is more frequent, more severe, and most dangerous for the workers with the least power to protect themselves. The harm it causes is foreseeable and, increasingly, so is the responsibility to prevent it.
