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

France banned asbestos from 1 January 1997. Buildings constructed before then may contain asbestos. Their age and appearance do not establish a diagnosis, and rules in other countries differ. Do not disturb suspect materials.

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 for trained wearers using a suitable, correctly fitted model in assessed working conditions. An FFP2 drops to 10 and an FFP1 to 4: table 9 of INRS ED 6106 gives the full scale, and Britain’s HSE uses a different assigned factor for FFP3 — 4, 10 and 20 for FFP1, FFP2 and FFP3. N95 and FFP3 are distinct certifications; their labels are not interchangeable.

Three consequences people miss:

• an FFP3 does not eliminate exposure;
• its effectiveness depends on fit, training and following the instructions; NR models are not reusable beyond a shift;
• it does not decontaminate clothing, hair or footwear.

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

The French lead-risk report required on sale concerns, in particular, homes built before 1 January 1949. This regulatory date does not certify that other buildings are lead-free.

Paint dust and flakes can be harmful when inhaled or swallowed, particularly for children. Do not scrape suspect coatings. A construction date does not replace an assessment.

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.

An improvised rescue can expose a second person to the same dangerous atmosphere. Do not enter to help: call emergency services from a safe place and describe the situation. Confined-space intervention requires trained teams and specific procedures.

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.

At the slightest doubt, abandon entry or leave without exposing yourself further. Do not plan a return until access and safety conditions have been established.

Tetanus and leptospirosis: two documented biological risks

Tetanus. The bacterium lives in soil and can enter through a wound or cut; the disease is not contagious. France recorded 48 cases and 14 deaths between 2012 and 2021. French guidance schedules adult boosters at 25, 45 and 65, then every ten years. Seek medical advice for a soiled wound, particularly if vaccination is not up to date; recommendations depend on the wound and vaccination history.

Leptospirosis. The bacterium can spread through animal urine, including rodents, via contaminated water or surfaces, wounds or mucous membranes. Santé publique France’s 2025 report records 562 notifications across France, including 274 in mainland France and Corsica (0.4 per 100,000). Of the 562 cases, 380, or 68 %, were hospitalised; 36 % of those hospitalised needed critical care. These proportions describe reported cases, not the individual risk of a visit.

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 in the EU. Mobile calls depend on available coverage: plan how to raise the alarm before visiting an isolated area.

In France, 114 provides accessible emergency contact, including SMS, an app and video calls, for people who have difficulty hearing or speaking.

Give emergency services your location and available landmarks, the number of people and the nature of the danger. Do not rely solely on automatic phone location.

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 guide concerns France. Public pages viewed without signing in do not provide exact access information. Member features are available on the website and in the app, according to access rights. Location information does not authorise entry. Check access conditions with the owner or site manager.