12 Aug Heat Stress – JSA

Heat Stress Job Safety Analysis (JSA)

Job / Task

Construction, maintenance, field, shop, warehouse, and other work performed in hot environments or under conditions that may expose employees to heat stress or heat illness.

Purpose

This Job Safety Analysis (JSA), also known as a Job Hazard Analysis (JHA), identifies hazards associated with occupational heat exposure and establishes safe work practices and controls to prevent heat rash, heat cramps, heat exhaustion, heat syncope, heat stroke, dehydration, and heat-related incidents.

Personnel Qualifications

Employees and supervisors shall understand the heat hazards associated with their work and the measures required to prevent and respond to heat illness.

Employees shall:

• Recognize common signs and symptoms of heat illness and immediately report symptoms in themselves or others.
• Understand the importance of hydration, rest, shade or cooling, and acclimatization.
• Follow established work/rest schedules and heat controls.
• Use the buddy system or other observation methods when required by conditions.
• Know how to summon emergency medical assistance and provide the worksite location.
• Never leave an employee suspected of serious heat illness alone.
• Stop work and seek assistance when heat symptoms develop or conditions become unsafe.

Required PPE

PPE shall be selected for the task while considering its effect on heat load and may include:

• Lightweight, breathable work clothing where compatible with the task.
• Hard hat and other required head protection.
• Safety glasses with side protection.
• Safety footwear appropriate for the work.
• Work gloves appropriate for the task.
• Cooling vests, cooling towels, or other approved cooling equipment when appropriate.
• Sun-protective clothing where applicable.
• Task-specific PPE required by the work activity or site.

Impermeable, chemical-resistant, arc-rated, flame-resistant, or other protective clothing may increase heat stress. Work practices, monitoring, rest periods, and cooling controls shall be adjusted accordingly.

JSA – Job Steps, Hazards, and Controls

Step 1 – Evaluate Heat Conditions Before Work

Potential Hazards

• High temperature or humidity.
• Direct sunlight or radiant heat.
• Heavy physical workload.
• Protective clothing increasing heat load.
• Employees not acclimatized to heat.

Required Controls

• Review expected temperature, humidity, sun exposure, workload, clothing, and work duration before starting.
• Use an appropriate heat-stress assessment method when conditions warrant it.
• Identify employees who are new to hot work or returning after an extended absence and provide increased observation and gradual exposure.
• Plan additional controls for strenuous work, enclosed areas, radiant heat, or heat-retaining PPE.
• Discuss heat hazards and controls during the pre-task briefing.

Step 2 – Establish Water, Rest, Shade, and Cooling

Potential Hazards

• Dehydration.
• Inadequate recovery.
• Progressive heat strain.
• Delayed access to cooling.

Required Controls

• Provide employees ready access to adequate potable drinking water.
• Encourage frequent drinking before thirst becomes pronounced.
• Provide shade, air-conditioned space, fans, ventilation, or another suitable cooling area as appropriate.
• Locate recovery areas so employees can reach them promptly.
• Provide additional rest and cooling as heat exposure or workload increases.

Step 3 – Acclimatize Employees

Potential Hazards

• Heat illness in new employees.
• Heat illness after absence from hot work.
• Overexertion during early exposure.

Required Controls

• Gradually increase heat exposure and workload for employees who are new to hot environments or have lost acclimatization.
• Provide closer supervision and observation during the acclimatization period.
• Avoid assigning unusually strenuous workloads to unacclimatized employees without additional controls.
• Adjust the acclimatization process when heat conditions become significantly more severe.

Step 4 – Begin Work in Hot Conditions

Potential Hazards

• Rapid heat buildup.
• Excessive exertion.
• Dehydration.
• Reduced concentration.

Required Controls

• Start adequately hydrated.
• Use mechanical aids and team handling to reduce physical workload when practical.
• Schedule strenuous activities during cooler periods when feasible.
• Rotate employees or modify tasks when needed to reduce individual heat exposure.
• Maintain access to drinking water throughout the work.

Step 5 – Monitor Employees During Work

Potential Hazards

• Heat exhaustion.
• Heat stroke.
• Heat cramps.
• Heat syncope.
• Confusion or impaired judgment.

Required Controls

• Observe employees for unusual fatigue, dizziness, headache, nausea, weakness, heavy sweating, confusion, altered behavior, or loss of coordination.
• Encourage employees to watch coworkers for signs of heat illness.
• Increase observation during high heat, strenuous work, acclimatization, or use of heat-retaining PPE.
• Immediately remove symptomatic employees from heat exposure and begin appropriate response procedures.
• Do not allow an employee with significant heat-illness symptoms to continue working.

Step 6 – Maintain Hydration

Potential Hazards

• Dehydration.
• Electrolyte imbalance.
• Reduced physical and mental performance.

Required Controls

• Drink water frequently in small amounts throughout the work period.
• Do not rely on thirst alone as an indicator of hydration needs.
• Ensure water supplies remain sanitary, accessible, and replenished.
• For prolonged heavy sweating, follow site guidance regarding appropriate electrolyte replacement.
• Avoid practices that interfere with adequate hydration.

Step 7 – Use Rest Breaks and Cooling

Potential Hazards

• Accumulated body heat.
• Fatigue.
• Inadequate recovery.
• Progression of heat illness.

Required Controls

• Take scheduled and additional rest breaks as required by conditions and employee symptoms.
• Use shaded or cooled recovery areas.
• Remove unnecessary PPE during recovery only when doing so does not create another hazard.
• Use approved cooling methods when appropriate.
• Do not shorten required recovery periods merely to maintain production.

Step 8 – Perform Strenuous Work

Potential Hazards

• High metabolic heat production.
• Rapid fatigue.
• Heat exhaustion or heat stroke.
• Reduced coordination.

Required Controls

• Reduce work intensity when environmental heat is elevated.
• Use mechanical equipment or additional employees to reduce exertion when practical.
• Increase rest frequency and cooling opportunities.
• Rotate strenuous tasks when appropriate.
• Closely monitor employees performing heavy work.

Step 9 – Work in Direct Sun or Near Radiant Heat

Potential Hazards

• Solar heat gain.
• Burns.
• Elevated body temperature.
• Dehydration.

Required Controls

• Provide shade where practical.
• Schedule work to reduce exposure during the hottest portion of the day when feasible.
• Use barriers, insulation, shielding, or increased distance from radiant heat sources when possible.
• Use appropriate sun-protective clothing compatible with the work.
• Increase hydration and recovery opportunities as exposure increases.

Step 10 – Work in Heat-Retaining PPE or Protective Clothing

Potential Hazards

• Reduced evaporative cooling.
• Rapid heat buildup.
• Dehydration.
• Heat exhaustion or heat stroke.

Required Controls

• Account for the additional heat burden created by protective clothing.
• Reduce work periods and increase recovery time as necessary.
• Use cooling garments or other approved controls when appropriate.
• Monitor employees more frequently.
• Provide a suitable area for safe removal of protective clothing and cooling.

Step 11 – Recognize and Respond to Heat Cramps or Heat Exhaustion

Potential Hazards

• Muscle cramps.
• Headache.
• Dizziness.
• Nausea.
• Weakness.
• Heavy sweating.
• Fainting.

Required Controls

• Stop the employee’s work and move the employee to a cooler or shaded location.
• Loosen or remove unnecessary outer clothing and begin active cooling as appropriate.
• Provide cool drinking water if the employee is alert and able to drink safely.
• Do not allow the employee to return to work until recovered and authorized under applicable procedures.
• Obtain medical assistance when symptoms are severe, worsen, or do not improve promptly.

Step 12 – Respond to Suspected Heat Stroke

Potential Hazards

• Life-threatening elevated body temperature.
• Confusion.
• Loss of consciousness.
• Seizure.
• Organ damage or death.

Required Controls

• Treat suspected heat stroke as a medical emergency.
• Call emergency medical services immediately.
• Move the employee to a cooler area and begin rapid active cooling while awaiting emergency responders.
• Use available cooling methods such as cold-water immersion when safely available, or wetting the employee and applying ice or cold packs to assist rapid cooling.
• Do not leave the employee alone.
• Do not give fluids to an unconscious, confused, vomiting, or otherwise unsafe-to-drink employee.
• Continue cooling and monitoring until emergency responders take over.

Step 13 – Respond to Changing or High-Heat Conditions

Potential Hazards

• Unexpected temperature increase.
• Equipment or ventilation failure.
• Loss of shade or water.
• Multiple employees developing symptoms.

Required Controls

• Reassess conditions when temperature, humidity, workload, clothing, ventilation, or work location changes.
• Increase water, rest, shade, cooling, monitoring, or work rotation as necessary.
• Suspend or reschedule work when heat hazards cannot be adequately controlled.
• Immediately correct loss of required water or cooling resources.
• Escalate controls when employees show signs of excessive heat strain.

Step 14 – Complete the Work and Recover

Potential Hazards

• Residual dehydration.
• Delayed heat symptoms.
• Fatigue affecting travel or later work.

Required Controls

• Allow adequate cooling and hydration after significant heat exposure.
• Report any heat-related symptoms that occur during or after the task.
• Do not assign additional strenuous work to an employee who has not adequately recovered.
• Evaluate heat-related incidents or symptoms to determine whether controls need improvement.

General Safe Work Requirements

• Heat exposure shall be evaluated based on environmental conditions, workload, duration, clothing, radiant heat, and employee acclimatization.
• Engineering and administrative controls shall be used to reduce heat exposure whenever practical.
• Potable drinking water shall be readily accessible throughout heat-exposed work.
• Employees shall be provided appropriate opportunities for rest, shade, and cooling.
• New or returning employees shall be gradually acclimatized to hot work and observed more closely.
• Employees shall be encouraged to report heat symptoms immediately without delaying for production concerns.
• Employees showing signs of heat illness shall be removed from heat exposure and evaluated promptly.
• Suspected heat stroke is a medical emergency requiring immediate emergency medical response and rapid cooling.
• No employee suspected of serious heat illness shall be left alone.
• Work shall be modified, suspended, or rescheduled when heat hazards cannot be adequately controlled.

Training

Employees and supervisors shall receive heat-stress training appropriate to their work. Training shall include heat-risk factors, acclimatization, hydration, water and recovery provisions, work/rest practices, effects of PPE and protective clothing, signs and symptoms of heat illness, employee monitoring, emergency response, rapid cooling for suspected heat stroke, communication with emergency medical services, and stop-work expectations.

References

• OSHA – Heat Injury and Illness Prevention guidance and applicable General Duty Clause requirements.
• NIOSH – Criteria for a Recommended Standard: Occupational Exposure to Heat and Hot Environments.
• ACGIH – Threshold Limit Values for Heat Stress and Strain, where used by the employer.
• Applicable state or local heat-illness prevention requirements.
• Applicable site Heat Illness Prevention or Thermal Stress Program.