SHIPYARD EMPLOYMENT

Protecting Workers from Heat Illness 

in Confined Spaces

Working in confined spaces can increase a worker’s risk of heat illness. 

• The temperature is often higher than outside air

• There is usually low airflow

• Personal protective equipment (PPE) can cause body overheating
Know the signs of heat illness

Take action at the first sign of heat illness. Heat illness can 

worsen quickly. When in doubt, call 911! 

If a worker experiences:

• Headache or nausea

• Weakness or dizziness

• Heavy sweating or hot, dry skin

• Elevated body temperature

• Thirst

• Decreased urine output

Take these actions:

• Leave the confined space

• Move to a cooler area

• Give water to drink

• Remove PPE and unnecessary

clothing

• Cool with water, ice, or a fan

• Do not leave alone

• Seek medical care if needed

9-1-1

The following are signs of a medical emergency!

• Abnormal thinking or behavior

• Slurred speech

• Seizures

• Loss of consciousness

CALL 911 IMMEDIATELY

COOL THE WORKER RIGHT AWAY WITH WATER OR ICE

STAY WITH THE WORKER UNTIL HELP ARRIVES

What you can do to prevent heat illness

Create a plan and provide training  

• Develop a plan that aids in

preventing heat illness and

communicate it to supervisors and

workers. Include elements such as

monitoring, acclimatization, workor rest- schedule, and emergencies.

• Train all workers on heat illness

risks, symptoms, and response

procedures, as well as prevention

measures.

Plan work schedules

• Allow new and returning workers

to build tolerance to heat

(acclimatize) and take frequent

breaks. Follow the 20% rule.

This safety practice prescribes

that no more than 20% of the

shift’s duration is worked at full

intensity in the heat for the first

day. Increase the duration of time

at full intensity by no more than

20% a day until workers are used

to working in the heat.

• Adjust work durations or period

of day work is scheduled based

on heat conditions. Consider

rotating jobs among workers.

• Allow frequent rest breaks.

Breaks should be long enough

for workers to recover from heat

given the temperature, humidity,

and working conditions.

Set controls and monitor 

on‐site activity

• Check the temperature in the

space before work. Use the

OSHA-NIOSH Heat Safety

Tool App when planning

outdoor activities.

• Ventilate the space to bring in

cooler air and create airflow.

• Implement a buddy system

where workers monitor

themselves and each other for

signs of heat illness.

• Designate a cool or shady area

for breaks.

• Provide cool drinking water.

Encourage workers to drink at

least 1 cup every 20 minutes.

• Have workers wear loosefitting, breathable clothing,

where possible.
For more information: 1-800-321-OSHA (6742) 

TTY 1-877-889-5627 

www.osha.gov/heat

For more information on other confined space hazards visit 

www.osha.gov/maritime.

Federal law entitles you to a safe workplace. You have the right to 

speak up about hazards without fear of retaliation. 

See www.osha.gov/workers for information about how to file a 

confidential complaint with OSHA and ask for an inspection.

Scan the QR code for more information.

OSHA 4274-04 2023