Role of carbon monoxide in seaplane crash was not considered until years later, inquest told

“…it appears that police and the ATSB wrongly assumed a chemical byproduct of carbon monoxide was routinely checked for in toxicology screening. Blood samples retained from the autopsies were examined, revealing all passengers had the chemical, carboxyhaemoglobin, in their systems.”

Sydney seaplane crash: Role of carbon monoxide not considered until years later, inquest told (smh.com.au)