Working in Hot Environments: What Must Enterprises Do to Protect Workers? | Wellbeing

With outdoor temperatures frequently exceeding 35°C and sometimes reaching 38-39°C at midday workers face severe risks to their health and lives. Enterprises bear not only a legal responsibility but also a moral obligation to take concrete, science-based actions to protect their workforce, minimize occupational accidents, and maintain stable productivity.

1. Severe Health Impacts of Hot Environments on Workers

1.1. Heat Stroke

When working in a hot environment, the human body must increase sweat secretion to cool down, leading to rapid dehydration and electrolyte imbalance. Heat Stroke is the most dangerous and life-threatening condition, occurring when the core body temperature exceeds 40°C and the body's natural thermoregulatory mechanisms completely collapse.

Symptoms often develop rapidly and severely. Initial signs include agitation, excruciating headaches, flushed/hot/dry skin (or sometimes profuse sweating), lethargy, shortness of breath, nausea, vomiting, and abdominal pain. Without prompt and correct medical intervention, the core temperature will quickly surpass 41°C. The victim will experience dizziness, a pale complexion, and a rapid pulse. In severe cases, this rapidly progresses to delirium, convulsions, coma, cardiovascular collapse, and death due to multi-organ failure.

1.2. Heat Exhaustion and Heat Cramps

Heat Exhaustion is more common, characterized by heavy sweating, pale skin, dizziness, muscle weakness, tachycardia (rapid heartbeat), and nausea. If left untreated, heat exhaustion can quickly escalate into heat stroke.

Heat cramps occur due to the loss of salt and potassium, causing severe muscle spasms, particularly in the arms and legs. Furthermore, sunburn from UV exposure increases the long-term risk of skin cancer, weakens the immune system, and elevates the risk of cardiovascular and respiratory diseases.

2. Employer Responsibilities: Environmental Assessment and Monitoring

Pursuant to the National Technical Regulation QCVN 26:2016/BYT on Workplace Microclimate:

• Facilities where employees are exposed to microclimate factors must conduct occupational environmental monitoring at least once a year, complying with the Labor Code and the Law on Occupational Safety and Health.

• Employers must provide adequate Personal Protective Equipment (PPE) suitable for the working environment.

If the workplace microclimate fails to meet permissible limits—for example, if the WBGT (Wet Bulb Globe Temperature) index exceeds 30°C for heavy labor or 26.7°C for medium labor—the employer must immediately implement corrective measures. This includes instantly reducing workload intensity, extending rest periods, or shifting work to cooler hours.

Additionally, to ensure a well-ventilated workspace, enterprises should install exhaust fans in enclosed environments, utilize thermal shields, deploy air conditioning (if feasible), and enhance factory ventilation. The temperature differential between indoors and outdoors should be maintained at a safe margin of 3°C - 6°C.

3. Administrative Controls and Work Organization

• Smart Scheduling: On days with extreme temperatures, schedule heavy tasks during the cooler parts of the day (early morning or late afternoon). Assign less physically demanding tasks during peak heat and limit outdoor exposure.

• Avoid Overexertion: Do not allow prolonged labor under direct sunlight or in high-humidity/high-heat environments.

• Periodic Rest Breaks: After 45 to 60 minutes of continuous work in a hot environment, workers must rest in a cool, shaded area for 10-15 minutes to recover energy and maintain performance. For heavy labor (construction, welding, manual transport) when temperatures exceed 38°C, continuous work should not exceed 30 minutes. Enterprises must establish rotation schedules ensuring each worker has at least 2-3 hours of indoor or shaded work per shift.

4. Medical and Nutritional Measures

• Frequent Hydration: Encourage workers to take small sips of water regularly every 15–20 minutes, rather than waiting until they feel thirsty.

• Electrolyte Replenishment: Workers can add a pinch of salt to their water or consume ORS (Oral Rehydration Salts), lemonade, or fruit juices (strictly avoiding alcohol and caffeine). Note: ORS should only be used when workers are dehydrated and genuinely need electrolyte replenishment. Overconsumption of electrolytes can cause adverse effects such as dizziness, palpitations, and in extreme cases, fatality.

• Health Monitoring & Nutrition: Closely monitor vulnerable individuals. Provide a nutritious diet rich in green vegetables and fruits to supply essential vitamins and minerals.

5. Personal Protective Measures (PPE)

• Appropriate Clothing: When working outdoors in the heat, workers should wear lightweight, breathable, sweat-absorbent, light-colored clothing made of cotton or khaki. Garments with a UPF 50+ rating are highly recommended to block UV rays.

• Heat-Resistant PPE: Always equip workers with sun-protection gear, including wide-brimmed hats with neck flaps, UV-blocking safety sunglasses, sunscreen, breathable safety shoes, and heat-resistant gloves if working near heat sources. Many progressive enterprises also provide cooling vests containing gel packs or wearable fan systems for continuous outdoor labor.

• Avoid Immediate Cold Showers: Workers should not take cold showers immediately after returning from the sun. Rapid temperature changes while the body is sweating profusely are dangerous and can trigger a stroke.

• Acclimatization and Fitness: Encourage regular physical exercise to build endurance and help the body acclimate to harsh weather conditions.

6. First Aid Training and Emergency Response Plans

All employees must undergo first aid training for heat stroke and heat exhaustion. Training should cover early recognition of signs: dizziness, nausea, hot/dry skin, confusion, and rapid breathing.

If someone is suspected of suffering from heat stroke, call emergency services (115) immediately. While waiting for the ambulance, perform these basic first aid steps:

• Check Vital Signs: Check the victim's pulse and breathing. If they are unresponsive and not breathing, commence CPR.

• Move to a Cool Area: Relocate the victim to a shaded or air-conditioned area.

• Loosen Clothing: Remove restrictive outer clothing and heavy PPE.

• Rapid Cooling: Apply cold, wet towels or ice packs to the armpits, back of the neck, and groin (areas with major blood vessels) to rapidly drop the core temperature. The goal is to lower the body temperature to approximately 38.3°C - 38.8°C.

• Hydration (If Conscious): Offer cool water or an electrolyte solution (ORS) only if the victim is fully conscious and able to swallow. Do not force them to drink.

7. Special Care for High-Risk Groups

At the enterprise level, managers and HSE officers must pay special attention to high-risk individuals, including:

• The elderly, young workers, and pregnant women.

• Workers performing high-intensity labor outdoors or in scorching environments (e.g., agricultural workers, brick kilns, steel foundries).

• Individuals with chronic diseases (hypertension, Chronic Obstructive Pulmonary Disease - COPD, asthma, diabetes).

These individuals require comprehensive medical screenings before being assigned to outdoor or high-heat tasks. Enterprises should have on-site medical staff during the hot season and conduct biannual health check-ups for this group. Workers taking diuretics, blood pressure medications, or those with a history of alcohol abuse must be monitored exceptionally closely.