Chemical burns can happen when the skin or eyes come into contact with acids, alkalis or other corrosive substances. They can occur at home, in workplaces, laboratories, workshops, farms and industrial environments.
Unlike an ordinary thermal burn, a chemical may continue damaging tissue while it remains in contact with the body. Rapid decontamination is therefore a key part of first aid.
This guide explains how to respond to a chemical burn, how to protect yourself from contamination, when to remove clothing, what to do with dry chemical powders and why you should not attempt to neutralise a chemical with another substance.
Important: protect yourself before helping. Do not touch a hazardous chemical with bare skin and do not enter an unsafe contaminated area without suitable protection.
A chemical burn happens when a corrosive or irritating substance damages the skin or other tissues.
Possible causes include:
The severity depends on the chemical involved, its concentration, how much contacted the body and how long it remained in contact.
Signs and symptoms can include:
Some chemical injuries may become more obvious over time, so do not assume a burn is minor simply because the skin initially looks relatively normal.
| Step | What to do | Why it matters |
|---|---|---|
| 1. Make the area safe | Keep away from spills, fumes and contaminated surfaces and use suitable protective equipment if available. | The chemical could injure the first aider as well as the casualty. |
| 2. Call for help | Call 999 or 112 for a severe chemical burn and provide details of the substance if known. | Serious chemical burns need emergency medical assessment. |
| 3. Remove dry chemical first | If the substance is a dry powder, carefully brush or pat it away before using water. | Adding water immediately to some dry chemicals can spread contamination. |
| 4. Remove contaminated clothing | Carefully remove clothing or jewellery contaminated with the chemical where this can be done safely. | Contaminated material can keep the chemical against the skin. |
| 5. Irrigate the burn | Flood the affected area with cool or lukewarm running water and continue while emergency help is arranged. | Water helps dilute and remove the chemical from the skin. |
For many chemical burns, yes.
St John Ambulance recommends flooding the burn with cool or lukewarm running water to disperse the chemical and stop continued burning.
Continue irrigation while waiting for emergency help where appropriate.
However, if you know exactly which chemical is involved, also check its product label or Safety Data Sheet because some substances may have specific emergency instructions.
Unlike ordinary thermal burns, there is not always one fixed irrigation time suitable for every chemical.
St John Ambulance advises continuing to flood a chemical burn with cool or lukewarm running water until the ambulance arrives in severe cases.
The chemical's Safety Data Sheet may also specify an irrigation duration.
The important principle is to start irrigation promptly and avoid unnecessary delays.
If a dry chemical powder is on the skin, carefully remove as much of the powder as possible before applying water.
St John Ambulance advises brushing or patting powder away from the skin.
When doing this:
Once the dry material has been removed, begin appropriate irrigation unless the product-specific instructions say otherwise.
Yes, where it can be removed safely.
Clothing soaked with a chemical can keep the substance against the skin and continue causing damage.
Carefully remove:
Avoid pulling contaminated clothing across unaffected skin.
If clothing is stuck to damaged tissue, do not tear it away.
Before touching the casualty:
St John Ambulance specifically recommends protective gloves and, where available, an apron and eye protection when helping someone with a chemical burn.
No.
Do not try to neutralise an acid by adding an alkali, or an alkali by adding an acid.
The chemical reaction could:
St John Ambulance specifically advises never attempting to neutralise acid or alkali burns unless trained to do so.
Use appropriate irrigation instead and follow the product-specific emergency instructions.
Do not delay decontamination while searching for an antidote.
St John Ambulance guidance specifically advises beginning treatment rather than delaying while trying to find a neutralising substance or antidote.
Chemical exposure to the eye requires immediate irrigation.
Where it is safe to do so:
For more information, see our First Aid for Eye Injuries guide.
Some chemical incidents involve both skin exposure and harmful fumes.
If fumes are present:
See our First Aid for Smoke & Fume Inhalation guide.
Call 999 or 112 for a severe chemical burn or if the casualty:
Give ambulance control as much information as possible about the chemical.
If possible, provide:
Do not put yourself at risk retrieving a chemical container from an unsafe area.
A Safety Data Sheet, or SDS, contains important information about a hazardous chemical.
It normally includes:
Section 4 normally covers first aid measures.
Workplaces using hazardous chemicals should make sure relevant SDS information can be accessed quickly during an emergency.
See our COSHH & First Aid Explained guide for further workplace information.
Strong acids can damage skin and deeper tissue.
If an acid contacts the skin:
The exact first aid instructions on the chemical's SDS should also be followed.
Strong alkalis can cause serious chemical burns and may penetrate tissues deeply.
Products that may contain strong alkalis include some:
The same core principles apply: protect yourself, remove the chemical, irrigate thoroughly and seek medical help.
Wet cement is strongly alkaline and can cause serious chemical burns after prolonged skin contact.
These injuries can be deceptive because severe pain may not develop immediately.
If wet cement contaminates clothing or skin:
Workers handling cement should follow workplace COSHH procedures and PPE requirements.
Household and industrial cleaning products can irritate or burn skin and eyes.
If exposure occurs:
Never mix household cleaning chemicals in an attempt to neutralise them. Mixing products such as bleach with other cleaners can release dangerous gases.
Laboratories may use concentrated acids, alkalis and other hazardous substances.
Emergency arrangements should include:
First aid provision should reflect the chemicals actually present rather than relying only on a generic first aid kit.
Industrial workplaces may use:
The COSHH assessment should identify foreseeable exposure and the appropriate emergency response.
See our Manufacturing Workplace Safety Explained guide for broader workplace safety information.
Some agricultural chemicals can irritate or burn skin or eyes.
Workers should:
See our Pesticide & Agricultural Chemical First Aid guide for more detailed agricultural exposure information.
If someone has deliberately had a corrosive substance thrown onto them:
Do not attempt to neutralise the chemical.
The immediate priority is thorough decontamination rather than quickly covering the injury.
Once irrigation is complete and the chemical has been removed, follow advice from healthcare professionals regarding covering the burn.
Do not trap residual chemical against the skin beneath a dressing.
No.
Do not apply:
These products can interfere with assessment and do not remove the chemical.
No.
Do not put ice directly onto a chemical burn.
Ice can cause additional tissue damage.
Use cool or lukewarm running water for appropriate irrigation instead.
Some incidents can cause more than one type of burn, for example an industrial accident involving both hot material and corrosive chemicals.
Remove ongoing chemical contamination first while continuing to protect yourself.
Once decontamination has taken place, the casualty may also require management for an ordinary thermal burn.
See our Burns & Scalds First Aid guide.
| Chemical burn | Thermal burn |
|---|---|
| Caused by a corrosive or irritating substance. | Caused by heat, flames, hot surfaces or hot liquids. |
| Contamination may continue damaging tissue until removed. | Burning generally stops once the heat source is removed. |
| Dry chemical powder may need to be brushed off before irrigation. | No dry chemical decontamination is required. |
| Product label and SDS may contain substance-specific instructions. | General thermal-burn cooling guidance usually applies. |
| First aider may also be at risk of contamination. | Secondary chemical contamination is not normally a concern. |
If a casualty becomes unresponsive:
See our First Aid for an Unconscious Person guide.
Yes.
A severe chemical burn can contribute to medical shock.
Possible signs include:
Call 999, keep the casualty warm without overheating the burned area and continue monitoring them.
See our First Aid for Shock guide.
Common mistakes include:
A standard first aid kit alone is not enough to manage many chemical burns.
The most important resources may be:
General first aid supplies may still be useful after decontamination or for other injuries associated with the incident.
You can view our range of first aid kits when reviewing general workplace or home first aid provision.
| Situation | What to do |
|---|---|
| Chemical still present | Protect yourself and stop further exposure. |
| Dry chemical powder | Carefully brush or pat it away before appropriate irrigation. |
| Contaminated clothing | Remove it carefully while avoiding further contamination. |
| Liquid chemical burn | Flood with cool or lukewarm running water and follow product-specific guidance. |
| Chemical in the eye | Begin irrigation immediately and obtain urgent medical help. |
| Severe chemical burn | Call 999 or 112 and continue irrigation while help is arranged. |
| Acid or alkali burn | Do not attempt to neutralise it with another chemical. |
| Fumes involved | Do not enter a contaminated atmosphere. Move to fresh air only if safe. |
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