Lester was born at Walytjatjata in the
Anangu Pitjantjatjara Yankunytjatjara Lands of South Australia in 1941. After the mist passed, his family's camp experienced sudden deaths, outbreaks of skin rashes,
vomiting,
diarrhoea and temporary and permanent
blindness. Yami has said that some of the people were so weak they could not get down to the nearby waterhole and skim the black scum off the water which came from the black cloud, and actually died of thirst. It is generally accepted that this black mist was
fallout from
British nuclear tests at Maralinga and Emu Junction which were taking place at that time. His most significant contribution to the rights of Aboriginal people was helping gain recognition for the atomic tests at Maralinga and an acknowledgement for the 1800 Aboriginal people affected. His actions helped lead to the
McClelland Royal Commission in 1985, which found significant radiation hazards still existed at the Maralinga test sites. Recommendations included group compensation for the
Maralinga Tjarutja people and an extensive, long-term cleanup operation to restore the land. ==Other activism==