Toxicity of boric acid, borax and other boron containing compounds: A review

Niels Hadrup, Marie Frederiksen, Anoop Kumar Sharma*

*Corresponding author for this work

Research output: Contribution to journalReviewpeer-review


Boron, often in the form of boric acid, is widely used as a flame retardant in insulation products, and although humans ingest boron through food, high exposure may lead to unwanted health effects. We assessed the toxicity of boric acid, borax and other forms of boron, after inhalation, dermal and oral exposure. After oral exposure, boron is absorbed over the gastrointestinal tract. Intact skin seems to pose a more effective barrier to boron than compromised skin. Boron excretion seems to mainly occur via the urine, although after skin exposure boron has been demonstrated in bile and gastrointestinal contents. Inhalation toxicity data are sparse, but one animal study showed reduced foetal weight after inhalation of cellulose that had a boric acid content of 20%. Skin exposure to boric acid has proven fatal in some cases, and the range of toxicity effects include abdominal as well as local effects on the skin. Fatalities from boric acid also have occurred after oral ingestion, and the endpoints in animals are weight loss and reproductive toxicity. Concerning genotoxicity studies, the overall picture indicates that boron-containing compounds are not genotoxic. There was no evidence of the carcinogenicity of boric acid in a 2-year study in mice.
Original languageEnglish
Article number104873
JournalRegulatory Toxicology and Pharmacology
Number of pages9
Publication statusPublished - 2021


Dive into the research topics of 'Toxicity of boric acid, borax and other boron containing compounds: A review'. Together they form a unique fingerprint.

Cite this