I thought I would spend a bit of time looking for papers on what dose of Boron/Borax can potentially be dangerous. I have glanced at “The Borax Conspiracy” which talks about Rex Newman taking 30mg of Borax per day. That is probably only a little bit more elemental Boron than the Boric Acid I take at 3mg of elemental Boron.
Obviously fatal doses vary between people. I found more deaths reported from Boron/Borate/Boric Acid poisoning than I found from over use of Vitamin D.
When eating the pesticide and cleaner Borax there are different versions with more or less water initially added. That will affect how hazardous this is.
I found one person who committed suicide by eating Boric Acid Crystals as well as all the cases in the review paper. (which I copy below)
4.2. Fatalities after human skin exposure
A 4-month-old girl was treated for dermatitis (“diaper rash”) for 1
week with boric acid ointment; but, as this did not relieve the symptoms,
she was further bathed in a boric acid solution and had her skin intermittently dusted with boric acid crystals. These latter treatments were
done over the next 2 weeks. The rash worsened, and the treatment with
boric acid was discontinued; the infant began having loose stools, and a
sore throat was treated with Argyrols (silver) and Vicks ointment
(containing several ingredients). The child developed difficulty breathing and was hospitalised. A range of signs and symptoms ensued, and
eventually the infant died. The blood level of boric acid was 22 mg/L
(3.9 mg B/L). The cerebrospinal fluid contained 50 mg boric acid/L (8.8
mg B/L). The tissue levels of boric acid were 36.8 mg B/kg (kidney),
17.5 mg B/kg (liver), 2.1 mg B/kg (brain), and 1.9 mg B/kg (muscle)—
levels considerably higher than the normal human levels presented in
Fig. 1. The 4-month-old twin brother of the former case was also hospitalised due to the same treatment regimen. The symptoms included
diarrhoea, vomiting and dehydration; his blood level of boric acid was
18.8 mg/L (3.3 mg B/L) and the urine level was 30 mg/L (5.3 mg B/L).
He eventually recovered (Ducey and Williams, 1953). A 35-year-old
woman who had varicose veins for a number of years treated a generalised rash for 14 days with wet dressings saturated with boric acid
solution. Some 11 days into the regimen, she became lethargic and
subsequently comatose; she later died. Her boric acid levels were as
follows: 138 mg B/kg (liver), 121 mg B/kg (brain), 166 mg B/kg (spinal
fluid), 919 mg B/kg (urine) and 613 mg B/kg (blood). These values are
considerably higher than the normal levels presented in Fig. 1 (Jordan
and Crissey, 1957). A 7-month-old infant died after being treated for
eczema for several days with dressings containing 3% boric acid. The
level of boric acid in bodily fluids and tissues were as follows: 44 mg
B/kg serum, 35 mg B/kg bile, 32 mg B/kg gastrointestinal tract contents,
21 mg B/kg brain, 18 mg B/kg kidney, 22 mg B/kg liver, and 32 mg B/kg
spleen (Kaufmann et al., 1962). A 9-month-old girl was admitted to the
hospital after having been treated for dermatitis (diaper rash) with boric
acid. She had erythema and excoriation of the skin; she had become
lethargic and semicomatose, with vomiting and high fever. A number of
additional symptoms were observed after hospitalisation, including
dehydration, cyanosis, and convulsions. She became comatose, and died
26 h after hospitalisation. Her boron tissue levels were 210 mg B/kg in
whole blood, 200 in serum, 240 in brain, 290 in liver, 280 in kidney, 220
in heart, 370 in thymus, 340 in muscle, and 30 in adipose tissue (Brooke
and Boogs, 1951).
5.2. Acute toxicity case studies with fatalities after ingestion of boric acid
Wong et al. described an accidental poisoning in which 5 of 11 infants died after ingesting infant formulae prepared from a bottle of
“distilled” water that accidently contained 2.5% boric acid. The amounts
of ingested borate was between 2 and 14 g—with a mean level in those
who died of 8.5 g borate (1.5 g B = 500 mg B/kg bw), and in those who
survived approximately 170 mg B/kg bw. The symptoms included central nervous system irritation; vomiting and diarrhoea; as well as erythema, exfoliation, and desquamation of the skin (Wong et al., 1964). A
man aged 77 years had ingested approximately 30 g of boric acid (~76
mg B/kg bw). He developed vomiting and diarrhoea, and acute renal
failure was suspected. He died from cardiac insufficiency (Ishii et al.,
1993). One man aged 45 years ingested approximately two cups of boric
acid crystals in a suicide attempt. He shortly thereafter experienced
nausea, vomiting, diarrhoea, and dehydration. After 2 days, he was
hospitalised with generalised erythematous rash, hypotension, renal
failure, and metabolic acidosis. He developed cardiac symptoms and
died. Fifty-two hours after ingestion his blood level of boric acid was 74
mg B/L and the urine level was 280 mg B/L (Restuccio et al., 1992). An
18-month-old girl died after accidently ingesting a pesticide that contained boric acid. The post-mortem examination showed cerebral
oedema and pulmonary congestion and oedema. The concentration of
borate in her heart blood was 14.6 mg B/L, and the concentration in the
gastric contents was 1060 mg B/L (Hamilton and Wolf, 2007). A male
infant 5 days of age had ingested 6–9 g boric acid (~300–500 mg B/kg
bw). He was irritable, hyperactive, and had erythema. Subsequently,
vomiting, central nervous system depression and desquamation of the
skin ensued; he became anuric and died (Segar, 1960).
Here are the EU Chemicals Agency reports
https://echa.europa.eu/registration-dossier/-/registered-dossier/15357
https://echa.europa.eu/registration-dossier/-/registered-dossier/15472/7/11/1
The first case is a 66 year-old man following the accidental ingestion of 1 to 1.5 oz of borax (sodium borate) powder mistaken for a saline cathartic and a second case in 1928 of a fatality in a 53-year-old woman following the ingestion of four pancakes made from flour containing 51% sodium borate. The authors found that the majority of acute boric acid ingestions produce no toxicity and that boric acid ingestions produce minimal toxicity at serum boric acid levels of 340 ug/mL or less. A review of previously reported cases indicate that much higher blood levels are well tolerated (Litovitz et al. 1988).
