Chemical Burns — Treatment and Decontamination

Chemical burns occur when a corrosive substance contacts the skin, eyes, or mucous membranes. Unlike thermal burns, chemical burns continue to cause damage as long as the chemical remains in contact with tissue — the burn is ongoing until the chemical is fully removed. Rapid and thorough irrigation with large volumes of water is the primary treatment and has more impact on outcome than almost any other first aid intervention.

Chemical burns occur at home from household cleaning products (bleach, drain unblocker, oven cleaner), in workshops and garages (battery acid, solvent strippers), and in industrial or agricultural settings. Understanding the correct response for each type prevents the injury from worsening and speeds recovery.

The Core Principle — Dilute and Remove

All chemical burn first aid is built around one principle: the chemical must be removed from contact with the tissue as quickly and completely as possible. Every second of continued contact causes additional tissue damage.

1. Remove the chemical immediately — by irrigation with large volumes of water
2. Do not attempt to neutralise — adding a base to an acid burn or an acid to an alkali burn can cause an exothermic reaction, generating heat and compounding the injury
3. Do not rub or scrub — this spreads the chemical and drives it into deeper tissue
4. Protect yourself — use gloves if available; avoid contaminating yourself during first aid

Immediate Response — All Chemical Burns

Step	Action
1. Remove from source	Move the person away from further exposure
2. Self-protection	Wear gloves; do not let the chemical contact you
3. Remove contaminated clothing	Gently remove clothing and jewellery in the affected area
4. Irrigate immediately	Cool running water directly on the burn — 20 minutes minimum
5. Call 999 or seek emergency care	All chemical burns require medical evaluation
6. Continue irrigation	If transport to hospital takes more than 20 minutes, irrigate during transport

⚠️ Do not attempt to neutralise acid burns with baking soda or alkali burns with vinegar. This sounds logical but the neutralisation reaction generates heat, which causes thermal injury on top of the chemical injury. Water dilution is the correct treatment — it does not generate heat.

Irrigation Technique

The quality of irrigation matters:

• Volume: Large volumes of water are needed — a gentle dribble is insufficient; use tap flow, a garden hose, or shower
• Duration: Minimum 20 minutes for most chemicals; 60 minutes for alkalis (see below)
• Temperature: Cool to lukewarm running water — not ice cold
• Direction: Direct flow away from contaminated areas to avoid spreading the chemical to clean skin
• Eyes: If chemical has contacted eyes, irrigate with water or sterile saline flowing from the inner corner of the eye outward; hold the eye open; 20–30 minutes minimum; seek emergency care immediately

Chemical-Specific Considerations

Alkalis (High pH — Most Damaging)

Alkalis include: sodium hydroxide (caustic soda, drain cleaner), potassium hydroxide, lime (calcium hydroxide), bleach, cement.

• Alkali burns are more severe than acid burns of equivalent concentration — alkalis cause liquefactive necrosis that penetrates deeper than acid burns
• Irrigation must be longer — minimum 60 minutes, compared to 20 minutes for acids
• May feel less painful initially — this is deceptive; alkali burns are often deeper than they appear
• Never attempt to neutralise with vinegar or acid

Common Alkali Source	Typical Concentration
Drain cleaner	Very high (30–50% NaOH)
Oven cleaner	High
Cement / lime	Moderate to high
Bleach	Low to moderate

Acids (Low pH)

Acids include: battery acid (sulphuric acid), hydrochloric acid, nitric acid, acetic acid (concentrated vinegar).

• Coagulative necrosis — acids cause a protein coagulate that acts as a partial barrier; burns may be less deep than equivalent alkali exposures
• Irrigation for 20 minutes minimum
• Do not attempt to neutralise with baking soda

Hydrofluoric Acid — Special Case

Hydrofluoric acid (HF) is used in glass etching, some rust removers, and industrial processes. It is uniquely dangerous:

• HF penetrates skin without immediately causing the pain that would indicate burning
• Fluoride ions cause deep tissue damage including bone decalcification
• Calcium gluconate gel should be applied to HF burns after thorough water irrigation — this binds the fluoride ions
• All HF exposures require emergency hospital treatment immediately — even small skin exposures can cause systemic toxicity
• If HF exposure is suspected, inform emergency services specifically — treatment differs from standard chemical burn management

Eye Chemical Burns

Chemical burns to the eyes are ophthalmological emergencies:

1. Irrigate immediately — hold the eye open under running water or cup water and let it flow over the open eye for 20–30 minutes
2. Remove contact lenses if present — after initial irrigation, not before
3. Do not rub the eye
4. Go to emergency eye department or A&E immediately following irrigation — even if the eye appears normal
5. Alkali eye burns are particularly serious and can cause permanent vision loss; the longer irrigation is delayed, the worse the outcome

What Not to Do

Action	Why Not
Neutralise acid with base or vice versa	Exothermic reaction causes thermal burn
Apply butter, oil, or cream	Traps chemical; causes infection
Rub the burn	Spreads chemical; drives it deeper
Stop irrigation because it feels better	The burn continues; irrigation must be completed
Remove clothing stuck to burn	Wait for medical team
Use ice or very cold water	Vasoconstriction worsens outcome

After First Aid

Following irrigation and emergency care:

• Chemical burns are assessed and classified by depth and area, similar to thermal burns
• Some chemical burns require surgical debridement (removal of damaged tissue)
• Eye burns require specialist ophthalmology follow-up
• Inhalation burns (from chemical vapours) require respiratory assessment

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Quick Reference

Chemical Type	Irrigation Duration	Special Note
Acids	20 minutes	Do not neutralise
Alkalis	60 minutes	More dangerous; deeper injury
Hydrofluoric acid	20 minutes + calcium gluconate	Emergency hospital immediately
Eyes (any chemical)	20–30 minutes	Emergency eye care immediately
All chemical burns	Do not neutralise	Water dilution only
All chemical burns	Do not rub	Spreads chemical
All chemical burns	Seek emergency care	After irrigation