”Small amounts of methanol are present in normal, healthy human individuals. One study found a mean of 4.5 ppm in the exhaled breath of test subjects.[19] The mean endogenous methanol in humans of 0.45 g/d may be metabolized from pectin found in fruit; one kilogram of apple produces up to 1.4 g of pectin (0.6 g of methanol.)[20]”
”Ingestion of as little as 3.16 grams of methanol can cause irreversible optic nerve damage, and the oral LD50 for humans is estimated to be 56.2 grams.[66]”
It doesn't mean it's safe to risk adding to the burden. The danger is that low-grade non-acute toxicity over the natural level could still be harmful over time. All it could take is one mutation.