"Although it does not appear to be carcinogenic, studies in dogs have reported testicular atrophy after exposure to 32 mg/kg bw/day for 90 days. This level is far lower than the LD50."
The base toxic dosage (on the order of multiple grams per kilogram bodyweight) is the reason it's typically labeled as very safe.
https://en.m.wikipedia.org/wiki/Boric_acid#Toxicology
"Although it does not appear to be carcinogenic, studies in dogs have reported testicular atrophy after exposure to 32 mg/kg bw/day for 90 days. This level is far lower than the LD50."
The base toxic dosage (on the order of multiple grams per kilogram bodyweight) is the reason it's typically labeled as very safe.