Abandoned buildings: what are the real risks?

What actually injures people in an abandoned building?

The French Ministry of the Interior listed it in 2020, answering a written parliamentary question about the dangers of urbex: structural collapse, chemical hazards, underground flooding, falls from height, injuries from sharp objects. The answer notes that teenagers and children are increasingly drawn to the activity.

Those five families share one trait: none of them announces itself. A floor holds until it does not. Oxygen-poor air has no smell and no colour. An asbestos fibre is invisible. That is what separates a derelict building from rough terrain — the hazard is hidden, and help arrives slowly.

How to recognise asbestos, and what a mask really changes

The ban date depends on where you are, and it is the date that matters.

France’s INRS maps where the material sits in a building: sprayed coatings, pipe lagging, false ceilings, lift shafts, floor tiles, partitions, plaster, roofing and buried pipework. Inhaled, the fibres cause pleural plaques, lung and pleural cancer — mesothelioma — and fibrosis. INRS notes that these effects usually appear years after exposure begins, and that asbestos remains the leading cause of work-related death outside accidents.

On masks, the gap between the label and reality is worth knowing. A disposable FFP3 filtering half-mask carries a nominal protection factor of 50: the standard’s laboratory requirement. INRS assigns that same mask a protection factor of 10, defined as the level expected in real use for 95 % of wearers. For an FFP2 it drops to 4, and a US N95 sits in the FFP2 band rather than the FFP3 band.

Three consequences people miss:

• an FFP3 reduces exposure, it does not remove it;
• it is single use, and it protects only if it seals against the face;
• it does nothing for clothes, hair and boots, which carry fibres home.

The only move that genuinely protects is not disturbing a suspect material, and not staying in a room where sprayed coatings or floor tiles are breaking up.

Lead paint: which buildings

France requires a lead exposure assessment for residential buildings built before 1 January 1949. In the United States, the federal government banned lead-based paint for housing in 1978, and the EPA and HUD disclosure rule still applies to most pre-1978 housing — roughly three quarters of which, by EPA’s own estimate, retains some lead paint.

Use whichever date applies where you are. The hazard is not brief contact; it is inhaling or swallowing the dust and flakes, and it is worst for children.

Why a cellar, a shaft or a tank can kill in minutes

INRS defines a confined space as a wholly or partly closed volume that was not designed to be occupied permanently. Its examples map onto exactly what draws people into a derelict site: wells, sewers, tanks, vessels, silos, crawl spaces, service galleries.

Four hazards are listed: oxygen-depleted atmosphere, so asphyxia; toxic gas or vapour, so poisoning; explosive atmosphere; and the difficulty of rescue and evacuation.

That last one is the least understood. In a confined space, the person who climbs down to help the first casualty is the second casualty. It is the pattern in every professional incident review. Teams who work in these spaces carry gas detection, forced ventilation, harnesses and a watcher outside. None of that can be improvised.

Floors, stairs, roof structures

No observation method replaces a structural survey, and this guide will not pretend otherwise. What can be said without inventing anything fits in three lines.

An abandoned building decays through water: a holed roof wets the floors, floors rot from underneath and give way without warning under a load they carried yesterday. A surface that looks sound may have lost its bearing. A rusted steel stair loses section where you cannot see it.

The practical conclusion is the one on our Safety page, and it does not move: at the slightest doubt, leave, and come back another time. The building will still be there.

Tetanus and leptospirosis: two documented biological risks

Tetanus. The bacterium lives in soil and enters through any wound, cut or ordinary graze; the disease is not contagious. France recorded 48 cases and 14 deaths between 2012 and 2021. French guidance schedules adult boosters at 25, at 45, then every ten years from 65. US CDC guidance is a booster every ten years, and after five years for a dirty or severe wound. A soiled wound in someone not up to date is a reason to see a doctor, not to wait.

Leptospirosis. Spread by rodent urine, it is caught through contact with fresh water or soiled surfaces, especially via a wound or the mucous membranes. In 2025 Santé publique France recorded 274 cases in mainland France and Corsica, a notification rate of 0.4 per 100,000. The number that matters is not the case count: 68 % of reported cases were hospitalised, and 36 % of those needed critical care.

A flooded basement, a damp cellar, a rat-frequented site: that is the exposure those bulletins describe.

What to carry

This table follows the equipment listed on our Safety page, with a column you rarely see elsewhere — what each item does not do.

What is useless: a surgical or cloth mask against fibres, an FFP1, a phone light as your main source of light.

Never alone, and always tell someone

Two rules appear in every set of recommendations, including our own Safety page, and neither costs anything.

1. Never alone. A twisted ankle on a staircase is a difficult exit for two people. Alone, in a place with no signal, it is a night on site.
2. Someone outside who knows. A person who stays out must know where you are, who you are with, and by what time you should have checked in. With no agreed return time, nobody knows when to start worrying.

How to call for help

112 is the European emergency number, free from any phone anywhere in the EU, and it also works in the United Kingdom alongside 999. In the United States and Canada, it is 911.

France’s 114 takes emergencies by text, video call and instant messaging. Created in 2011 for deaf and hard-of-hearing people, it also helps when speaking is impossible: no voice, no breath, or somewhere you must not make noise. The UK runs an equivalent emergency SMS service, which requires registering the phone in advance — do it before you need it, not after.

Since 2020, advanced mobile location is standard across mainland France: dialling an emergency number makes the handset compute its position and send it to the control room. It does not excuse you from describing where you are, but it gives a starting point when you no longer know.

And if you find something serious — a person in danger, damage in progress — the rule from our Safety page holds: leave, call, touch nothing.

What this guide does not do

It does not explain how to get into anywhere, how to get past a fence, or how to avoid being stopped. It describes hazards measured by public bodies and cites its sources.

The legal framework, with the articles and the penalties, is a separate guide, and it covers France only. And nowhere on this site is a coordinate published: pages name a place, locate it down to the department or state, and describe it, never further.