I don't remember where the VA came up before but this is the stuff they did to Agent Orange vets too. They pretended it wasn’t real until many died and suffered needlessly.
The data is unavailable because the US government classified it to cover their own gross negligence, just like Vietnam.
https://www.usnews.com/news/politics/articles/2022-06-16/senate-set-to-enhance-benefits-for-vets-exposed-to-burn-pits?context=amp