Borax is often touted as a wonder ingredient for natural cleaning in recipes like homemade cleaners and even in homemade beauty products as a preservative. It is a recipe in my popular All-Purpose Cleaner and laundry detergent, so I’ve gotten so many questions about the safety of borax that I decided it deserved more research and it’s own post.
What is Borax?
Borax, of the mule team variety, is sodium tetraborate or sodium borate (to get all official for a second) and NOT boric acid (hydrogen borate), which is a common misconception on the interwebs apparently.
Sodium Tetraborate (hereafter referred to as Borax) is a salt of boric acid but it is not chemically the same as boric acid. If you’ve read an article claiming borax is dangerous that goes on about the dangers of boric acid or says they are the same thing, I would not consider that article credible.
Borax vs. Boric Acid vs. Sodium Borate
Both are used as natural pesticides, which is probably the reason for the misconception, but boric acid carries a risk for toxicity at a much lower dose than borax does if ingested.
Borax is used in the process of making boric acid, but there is a tremendous chemical difference between the two. Borax is a naturally occurring mineral, though of course, that doesn’t make it inert or safe either. Arsenic is a naturally occurring metalloid but it isn’t safe for human use. Natural doesn’t always mean safe.
At the same time, the studies used to back up the safety (or danger) of borax often use boric acid or are ambiguous about which was used.
The product safety data on Borax also combines borax and boric acid, and it is unclear which substance the various warnings pertain to, but they list cautions like:
This product is white, odorless, crystalline powder. Direct contact with eyes may cause severe irritation with redness, pain, blurred vision, and possibly corneal injury. Repeated or prolonged excessive exposure with skin can result in irritation.
No chronic health effects are expected from the intended use of these products or from foreseeable handling of them in the workplace. Nonetheless, the following effects have been reported for a component, sodium borate, and boric acid. Sodium borate upon entry into the body becomes boric acid. Sodium borate and boric acid interfere with sperm production, damage the testes and interfere with male fertility when given to animals by mouth at high doses.
So the most menacing warnings about substances related to borax (including boric acid) relate the skin contact, eye contact or when it was “given ..by mouth at high doses.”
You know what else can irritate the eyes and skin and even cause digestive problems at high doses? Vinegar, and oregano essential oil (caused a cornea burn in my mother in law) and probably cayenne pepper too. That doesn’t mean that those things aren’t safe but just that they must be used safely. Borax is extremely alkaline, which makes it irritating when used undiluted.
Makes sense not to use any form: borax, sodium borate or boric acid as an eye wash, skin scrub or drink it, but it doesn’t answer the question about if occasional indirect contact (in things like cleaning products) is safe.
That data sheet does give borax a safety rating of “1” which is the same as baking soda and salt. (I wouldn’t recommend putting those in your eye or rubbing large amounts on the skin constantly or ingesting large amounts daily either)
The Environmental Working Group lists Borax as a safety rating of 5-6, though again, the studies used contained both borax and boric acid and the warnings referred to ingestion, eye contact or prolonged undiluted use.
What about Boron?
Boron, is a chemical element (atomic number 5) and a fascinating character (because I am a dork and easily fascinated by chemistry). There is a biological need for boron in small amounts, and things in the boron family are considered non-toxic to humans but dangerous to insects (thus the use as a pesticide):
In biology, borates have low toxicity in mammals (similar to table salt), but are more toxic to arthropods and are used as insecticides. Boric acid is mildly antimicrobial, and a natural boron-containing organic antibiotic is known. Boron is essential to life. Small amounts of boron compounds play a strengthening role in the cell walls of all plants, making boron necessary in soils. Experiments indicate a role for boron as an ultratrace element in animals, but its role in animal physiology is unknown.
Back to Borax… Toxic or Not?
There are a lot of confounding factors based on the source. The main points I found in researching were:
- Actual warnings for Borax use relate to avoiding eye contact, undiluted skin contact and ingestion.
- Borax is banned for food use by the FDA and the ECA (European Chemicals Agency) considered a substance of high concern but didn’t provide any documentation other than soil level dangers
- I was unable to find any studies that proved a danger to borax in natural cleaning products in diluted amounts as long as it didn’t get into the eyes or wasn’t ingested.
- The Skin Base Database classified Borax as moderate hazard, but most of the studies and listings related to borax use in food.
The Bottom Line: Is Borax Safe?
I could not find any data that was compelling enough for me to avoid natural borax powder completely. Obviously, I would not ingest it or feel comfortable using it in cosmetic or food preparations.
At the same time, most products I use borax in (like All-purpose Cleaner and Laundry Detergent) aren’t coming in direct, undiluted contact with my skin, I’m not ingesting them and I’m not getting them in or near my eyes, so most of the concerns and warnings with borax are not valid.
Also, I’m using homemade products with borax to replace things like regular laundry detergent or cleaners that rate “D” or “F” on the EWG Database.
Borax is an effective natural cleaner and a safer alternative to many conventional cleaners. Yes, it is also a pesticide, but a natural one (and great at getting rid of ants- here’s a great tutorial) but I’m yet to find conclusive evidence that it is either safe or harmful to humans (other than if it is ingested, rubbed in the eyes, etc).
I still consider borax safe for use in natural cleaning, but absolutely do your own research and make sure you are using in any capacity. I use a natural borax powder from Mountain Rose Herbs so it is free of any added surfactants or detergents, but Mule Team Borax is also considered a pure/natural form of borax.
Do you use Borax? Do you consider it safe?