Maisan Chamuset speaks through a small pipe inserted in his throat. Diagnosed with throat cancer six years ago, the 74-year-old has not sounded like himself since. His wife died of stomach cancer in 2018. In Kargi, a desert settlement in northern Kenya, his experience is routine.

More than 500 people have reportedly died from cancers affecting the digestive system — primarily the oesophagus and stomach — in the villages of Marsabit County, according to residents and local health workers cited by Al Jazeera. Many blame toxic waste left behind during oil exploration by Amoco, later acquired by BP, between 1986 and 1989.

At former drilling sites in the Chalbi Desert, a rusting pipe marked “Amoco Kenya” still sits beside patches of a white, powdery substance scattered across the ground. Some residents recall mistaking the material for salt and seasoning food with it. Worowa Bayo, who worked at one of the sites, said workers dug large pits, dumped waste into them at night, and covered them over by morning.

Independent tests have since indicated possible heavy metal contamination of local water sources. Scientists have not established a definitive causal link to the cancers, partly because long-term research has been thin. The medical record is less ambiguous: records from Kargi’s only health facility between 2006 and 2009 documented multiple cancer-related deaths, many involving the throat. That clinic, which once served roughly 6,000 people, is now shuttered.

Now 298 petitioners are suing BP and the Kenyan government at the Environment and Land Court in Isiolo. Their lawyer, Kelvin Kubai, calls it “environmental genocide.” They want a full environmental assessment, access to safe water, and compensation for affected families and livestock losses.

BP declined Al Jazeera’s request for an interview. Its legal team has appeared in court.

The case may take years. In Kargi, new cancer cases keep emerging, and Chamuset still speaks through his pipe.