Pre FDA

 In the early 1900s the US Dept. of Agriculture enlisted a group of men to eat meals with known contaminants, from formaldehyde to sulfuric acid to borax. The job was necessary because at the time food manufacturers were free to put anything into their products. A baseline needed to be established to determine safe levels of additives so the poison squad was formed. The men were fed three meals a day in exchange for reporting the symptoms they were experiencing. It did lead to the eventual cracking down on food producers and banning harmful ingredients, after which the poison squad was disbanded as they were no longer needed and surprisingly no one died.