Molten substance burns happen in foundries, welding, road surfacing, plastics and chemical industries when hot metal, plastic or bitumen splashes or sticks to the skin. These burns are particularly damaging because the substance is far hotter than boiling water and keeps heating tissue until it cools. The approach is to cool quickly with water, avoid pulling off hardened material and get medical help. Phosphorus burns from flares, fireworks and some chemicals need extra steps.
Molten Substance Burns First Aid: 6 Steps
- Remove the person from danger and call the ambulance for anything more than a small, superficial burn.
- Cool immediately with plenty of cool running water for up to 30 minutes. Water cools the substance and the tissue under it. Use a safety shower if available.
- Do not remove the substance once it solidifies. Pulling it away will tear off skin. The only exception is if it blocks the airway.
- Remove jewellery, watches and tight clothing near the burn before swelling, but do not pull off clothing that has melted into the skin.
- Cover loosely with a clean, non-fluffy, non-stick dressing, over the cooled substance, and keep the person warm.
- Seek urgent medical help, and treat shock if it develops.
If Molten Material Encircles a Limb
Hardened plastic, metal or bitumen that completely wraps a hand, arm or leg can tighten as swelling develops and cut off blood flow. If help will be delayed and you are trained, medical staff may advise splitting it lengthways while continuing to cool. Do not attempt this without direction and keep the limb raised and under observation for numbness, coldness, paleness or blueness of the fingers or toes.
Bitumen and Hot Tar
Cool the burn with running water and do not scrape or peel off the bitumen. Hospital staff use special solvents to loosen it. Remove bitumen only if it is blocking the airway or eyes, and even then use water and keep the person upright. Treat the burn using the steps in our burns first aid guide.
Phosphorus Burns
Phosphorus ignites when exposed to air. Keep the burned area wet or immersed in water, and keep dressings wet during transport. If particles are visible, remove them with forceps or tweezers, never with bare fingers. Do not use oil-based dressings. Protect your own skin and eyes, and call emergency services.
Preventing Molten Substance Burns at Work
Use face shields, heat-resistant aprons, gaiters and gloves around molten metals, keep work areas dry because moisture causes spattering, train staff in molten substance burns first aid and keep a safety shower and clean cooling water close at hand. Use our burn assessment guide to judge severity and the chemical burns guide when chemicals are involved.
Frequently Asked Questions
Should I pull hardened plastic or metal from the skin?
No. It will tear the tissue. Cool it and leave removal to medical staff.
How long should I cool molten substance burns?
Up to 30 minutes with cool running water, unless the person begins to shiver, in which case keep them warm.
References and Further Reading
Last updated: November 2026
Prepared by: EHS Guidelines Editorial Team
This article is general educational information and is not a substitute for accredited first aid training or professional medical care. In an emergency, call your local emergency number immediately. Emergency numbers, medicines and protocols differ between countries, so follow local guidance.
Related Guides
- Burn Assessment: Rule of Nines, Burn Depth and Serious Burns
- Burns First Aid: Treating Flame Burns and Scalds Step by Step
- Chemical Burns: First Aid for Skin Splashes and Absorbed Poisons
- Shock First Aid: Recognising Circulatory Shock and Acting Fast
- Electric Shock First Aid: Make the Scene Safe Before You Touch the Casualty
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