A Canary in the Coal tip? Climate change, coaltips and home insurance 60 years after Aberfan.

Sixty years after the Aberfan disaster of 21 October 1966, Wales lives with the legacy of the fossil fuel revolution. The nation has 368 disused coal tips that pose a potential risk to public safety as climate change starts to impact. This research estimates that 135,653 households, one in ten in Wales, live within a kilometre of a potentially dangerous coaltip site, October 2026.

What happened at Aberfan, and could it happen again?

On the morning of 21 October 1966, heavy rain caused a coal tip to collapse above the village of Aberfan, near Merthyr Tydfil. It slid downhill into Pantglas Junior School and a row of houses, 144 people were killed, 116 of them children. The tribunal that followed found the National Coal Board responsible, and Parliament passed the Mines and Quarries (Tips) Act 1969, the first law to regulate tip safety.

Sixty years on, the tips are still there. The Welsh Government listed 2,589 disused coal tips in its latest Spring 2026 data, 368 of them graded Categories C and D and in need of regular inspection. These are the coal tips that worry the authorities most. Two recent coal tip slides show the risk is not historical: at Tylorstown in Rhondda Cynon Taf during Storm Dennis in February 2020, and at Cwmtillery in Blaenau Gwent during Storm Bert in November 2024. Neither killed anyone. Both happened on tips above homes, in heavy rain.

The Welsh Government linked the 2020 incident to climate change and has been taking action to make coal tips safer, noting: "As the impact of climate change makes extreme weather events more powerful and more frequent, the Welsh Government is committed to keeping our communities safe."

How many disused coal tips are still a risk in Wales today?

There are 85 Category D tips and 283 Category C tips in Wales, 368 in total, out of 2,589 on the coal tip register (Spring 2026). The number of C and D tips rose from 360 in 2025 to 368 in Autumn 2025. Of the eight added, six were existing tips re-rated from Category A on their first full inspection.

Which places in south Wales are most exposed to coal tips?

Rhondda Cynon Taf has 85 Category C and D tips, the most of any council, including 29 of the 85 Category D tips in Wales. Merthyr Tydfil has 60 and Caerphilly 53. Measured by people rather than tips, Merthyr Tydfil has 17,624 households within a kilometre of a C or D tip, 68.4% of all households in the borough; Blaenau Gwent 19,833 (65.4%); Rhondda Cynon Taf 41,624 (40.3%). Across Wales, 135,653 households, 10.1% of the total, are within a kilometre of one.

Does climate change make coal tips more dangerous?

Hotter air can hold more moisture and there are concerns that with global warming this is resulting in wetter and more intense periods of rain during winter in the UK. The UK Met Office says that, on average, winters will continue to become wetter and summers drier.

Are insurers refusing to insure homes in coal tip areas?

We collected nearly 500 home building insurance quotes and found a much wider variation in the price insurers quoted for homes closer to coaltips, a phenomenon known as "price dispersion". This could indicate the insurance market is finding it harder to agree on risk for properties near to category C or D coal tips. There was no significant difference in price quotes for homes within 500 metres or 3km of a coal tip, however, homes in coaltip areas generally were more expensive to insure than the Welsh average. In addition there was evidence of insurers withdrawing the cheapest policy option available on some properties in coal tip areas.

Across the 387 priced quotes for homes within 1km of a tip, the median cheapest offer was £213 (lower quartile £152, upper quartile £326). 33 of 420 quote attempts (7.9%) were refused outright, and seven homes were refused by every insurer tried. In 30 of the 387 priced quotes (7.8%) the insurer priced higher policy tiers but did not offer its cheapest policy option: 18 of 154 with Direct Line, 12 of 142 with Churchill, none of 73 with Admiral. Where the same home was quoted by two or more insurers, the dearest offer was typically 1.6 times the cheapest.

Who is responsible for making coal tips safe, and what is being done?

Until April 2027, disused tips will be inspected and maintained by local authorities and Natural Resources Wales, with the Mining Remediation Authority involved in identifying and categorising tips. The Disused Mine and Quarry Tips (Wales) Act 2025 created a new body, the Disused Tips Authority for Wales, which takes responsibility for tip safety from April 2027: it must keep a register, assess every disused tip, monitor the registered ones, and can carry out works. The Welsh and UK Government restarted their joint Disused Mine and Quarry Tips Task Force on 17 March 2026, and consulted on guidance to the new Authority between 29 June and 18 September 2026.

How this research was done, and how to query it

The council figures are the Welsh Government's register counts; the homes-within-1km figures are Round Our Way's analysis, built by Campaign Salience from the register, OS Code-Point Open, the ONS Postcode Directory (May 2025) and Census 2021 household counts shared across live residential postcodes. An MCP connector that answers questions about any Welsh council by name, and refuses with a reason when the data cannot answer, follows shortly; the method will be published with it. See also how we make a report something AI assistants cite.

Updated 11 October 2026. Licence: CC BY 4.0, attribution to Round Our Way and Campaign Salience.