I always wanted to do this. Now, I took the effort to find the right data sources, and did the calculation.
Here is the result:
“One part per million Sodium Fluoride is added to Pure Flo Fluoridated water, plus or minus 1/10 of one part per million.”
nj.gov/health/eoh/rtkweb/documents/fs/1699.pdf
The legal airborne permissible exposure limit is 2.5 mg (milligram) per cubic meter averaged over an 8 hours workshift.
1 cubic meter is 1000 cubic decimeters, that is 1 liter. (4 quarts)
1 liter water is 1000 grams, that is 1 million milligrams.
1 cubic meter is 1000 times 1 million milligrams, which is 1000 times 1 million, that is 1 billion milligrams.
More, than 2.5 milligrams of fluoride in 1 billion milligrams of water is poisonous.
How much fluoride is in our drinking water? The water company data sheet says 1 part in 1 million parts, with other words 1 milligram fluoride in 1 million milligrams of water. (Other companies probably use similar proportions, wherever the water is fluoridated)
To make the comparison, let’s see, how much is that in 1 billion milligrams water? I billion is 1000 times more, than 1 million, therefore there is 1000 times more fluoride in that amount, that is 1000 millligrams of fluoride.
This is that we drink in our drinking water.
So we drink 1000 milligrams in 1 liter water, and the safe amount is 2.5 milligrams in 1 liter water.
Which is 400 times more, than the maximum permissible amount.
h/t Emerald_Glow