> However, in 2000, the warning labels were removed because scientists learned that rodents, unlike humans, have a unique combination of high pH, high calcium phosphate, and high protein levels in their urine.[34][35] One or more of the proteins that are more prevalent in male rats combine with calcium phosphate and saccharin to produce microcrystals that damage the lining of the bladder. Over time, the rat's bladder responds to this damage by overproducing cells to repair the damage, which leads to tumor formation. Since this does not occur in humans, there is no elevated risk of bladder cancer.[36]

I work in the biosciences (in a role between lab tech and actual scientist). So many things are provisionally accepted simply because you don't have the time or resources to verify them. Which is not too different from any other job, it just seems weird in the context of the sciences.