5 ms·

Total layman here. Question: if 5ppm in drinking water is safe, which would imply we deem it safe to drink unlimited amount of water with 5ppm benzene in it for

Total layman here. Question: if 5ppm in drinking water is safe, which would imply we deem it safe to drink unlimited amount of water with 5ppm benzene in it for our entire lives; would it really be problematic to use hand sanitizers with 15ppm (3x) for a few months? (Also considering, as other commenters in this thread say, ingesting benzene through skin is less efficient compared to drinking, according to some claims). I've no idea how they determine safe ranges for these chemicals, but as an engineer, I'm thinking if I were to do something like this, I'd leave some wiggle room. Like if I say 5ppm is safe, but if noticeable amount of people get leukemia with 10ppm, I would consider my job failed. Because 5ppm, although is safe, is too close to the danger zone therefore is not practical. So I'd guess small perturbations around 5ppm would not have noticeable affects (again, I'm a total layman, this is a question, not a claim).

akiselev 6y ago
Nit: it's parts per billion, million - only OSHA benzene exposure limits are measured in the millions and that's for industries working with benzene (and only for a short exposures). The kinetics of benzene in drinking water are very different than in hand sanitizer. Carcinogens in general have different risk profiles than other toxins like heavy metals or poisons because localized concentrations can be just as dangerous since a tumor can form and metastasize pretty much anywhere. Asbestos, for example, is much less dangerous in drinking water than in the air because the lubrication provided by water significantly reduces the physical damage caused by the fibers. Benzene (probably [1]) bioaccumulates in skin far more readily than in the digestive tract where the water is a diluting agent that reduces the probability of the benzene sticking around in the body. Since there is a lot less volume of blood flow in the tiny capillaries near the skin and hand sanitizer is designed to evaporate, there's a far higher risk of carcinogenic concentrations of benzene building up, especially around cuts or lesions. It's very plausible that a few mL of sanitizer with ppb concentrations of benzene can accumulate in small microliter pockets of tissue with concentrations in the 10s or 100s of ppm if continually applied throughout the day for months on end. Throw in the rapid pace of reproduction of skin cells and that's a legitimate cause for concern. [1] last I looked, it wasn't well studied in humans, but since benzene is a solvent and known to accumulate in leaves and bark, it strongly implies it has the same effect up and down the food chain.

akiselev 6y ago

Nit: it's parts per billion, million - only OSHA benzene exposure limits are measured in the millions and that's for industries working with benzene (and only for a short exposures). The kinetics of benzene in drinking water are very different than in hand sanitizer. Carcinogens in general have different risk profiles than other toxins like heavy metals or poisons because localized concentrations can be just as dangerous since a tumor can form and metastasize pretty much anywhere. Asbestos, for example, is much less dangerous in drinking water than in the air because the lubrication provided by water significantly reduces the physical damage caused by the fibers. Benzene (probably [1]) bioaccumulates in skin far more readily than in the digestive tract where the water is a diluting agent that reduces the probability of the benzene sticking around in the body. Since there is a lot less volume of blood flow in the tiny capillaries near the skin and hand sanitizer is designed to evaporate, there's a far higher risk of carcinogenic concentrations of benzene building up, especially around cuts or lesions. It's very plausible that a few mL of sanitizer with ppb concentrations of benzene can accumulate in small microliter pockets of tissue with concentrations in the 10s or 100s of ppm if continually applied throughout the day for months on end. Throw in the rapid pace of reproduction of skin cells and that's a legitimate cause for concern. [1] last I looked, it wasn't well studied in humans, but since benzene is a solvent and known to accumulate in leaves and bark, it strongly implies it has the same effect up and down the food chain.