Britain's acid tar lagoons have been around since the 1960s, when quarries were filled with hazardous waste. The pits have been left to pollute local land, with many people unaware they’re even close by. The Environment Agency claims there are only two in the country, but a Sky News investigation has officially identified 34, although there could be as many as 150.

In this episode, host Jayne Secker speaks to Sky correspondent Inzamam Rashid; Amy Roberts, a PhD student specialising in the topic, and Paul Pemberton, a local councillor who lives close to the Llwyneinion acid tar lagoon.