SEA/General/TBT-SEA-016

Cold Water Shock Awareness

Seasonal & Weather › General › Cold Water Shock Awareness

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Cold water shock is the body's involuntary response to sudden immersion in water below 15°C.
The gasp reflex on entering cold water can cause drowning within seconds if the head is submerged.
Heart rate and blood pressure spike dramatically, which can cause cardiac arrest in vulnerable workers.
UK inland waters rarely exceed 15°C, meaning cold water shock risk is present year-round.
Construction workers fall into rivers, canals, excavations, and process tanks throughout the year.
Even strong swimmers can drown from cold water shock because the gasp reflex is involuntary.
The initial shock response lasts approximately one to three minutes after immersion.
Wearing a PFD keeps the head above water during the critical first minutes of cold water shock.
Hypothermia follows cold water shock but takes longer to develop — typically fifteen to thirty minutes.
Rescue from cold water must be rapid because swimming ability deteriorates within minutes of immersion.

Prevent drowning	Cold water shock causes an involuntary gasp that fills the lungs with water, leading to drowning in seconds.
Year-round risk	UK waters are cold enough to trigger cold water shock in every season, not just winter months.
Rapid rescue needed	Swimming ability fails within minutes of cold water immersion — rescue plans must be immediate and rehearsed.

Don't

Wear a PFD whenever working within two metres of open or deep water on site
Brief all workers on the signs of cold water shock before starting waterside tasks
Ensure rescue equipment including throw lines and lifebuoys is positioned at water edges
Practice the rescue plan so all team members know their role in a water emergency
If you fall in, try to float on your back and control your breathing for one minute
Keep your head above water and resist the urge to swim until the shock passes
Call for help immediately and grab any available flotation aid or fixed structure
Pull casualties from the water horizontally to reduce the risk of cardiac complications
Treat anyone rescued from cold water for hypothermia even if they appear alert
Report all near misses involving water to improve controls and rescue readiness

DON'T assume you can handle cold water because you are a strong swimmer
DON'T work near open water without wearing a correctly fitted PFD
DON'T jump into cold water to rescue someone unless you are trained and equipped
DON'T ignore the risk in summer — UK waters are cold enough year-round for shock
DON'T let a rescued person stand up or walk immediately — keep them horizontal
DON'T remove wet clothing from a casualty in the open — wrap them in blankets instead
DON'T give hot drinks to someone in severe hypothermia — rewarm gradually
DON'T rely on swimming ability alone — cold water shock disables even expert swimmers
DON'T work near water without checking rescue equipment is in place and accessible
DON'T delay calling emergency services — cold water casualties deteriorate rapidly

See also: Drowning Prevention and Water Safety | Winter Working Safety

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