Editing Borax (section)

== Toxicity ==
According to one study, borax is not acutely toxic. Its {{LD50}} (median lethal dose) score is tested at 2.66 g/kg in rats, meaning that a significant dose of the chemical is needed to cause severe symptoms or death.

The lethal dose is not necessarily the same for humans; human studies in three borate exposure-rich comparison groups (U.S. Borax mine and production facility workers, Chinese boron workers, Turkish residents living near boron rich regions) produced no indicators of developmental toxicity in blood and semen tests. The highest estimated exposure was 5&nbsp;mg B/kg/day, likely due to eating in contaminated workplaces, more than 100 times the average daily exposure.<ref name="CLH2018">{{cite web |title= CLH report for boric acid – Proposal for Harmonised Classification and Labelling |publisher= Bureau for Chemical Substances |url= https://echa.europa.eu/documents/10162/23665416/clh_rep_boric_acid_5521_en.pdf/ee39f026-9d2d-28f7-5d90-63a424112162 |date= 23 April 2018 |access-date= 18 October 2018 |place= Lodz, Poland }}</ref>

Borax is absorbed poorly through intact skin, although fatalities have been recorded in persistent treatment of rashes and open wounds with boric acid-containing ointments and bath solutions. Borax is readily absorbed orally, well above 90%, and mostly excreted through the urine. Fatal cases attributed to ingestion include small children mistakenly drinking pesticides or suicide attempts with large volumes of crystals. No genotoxicity or carcinogenicity has been recorded in studies.<ref>{{cite journal  | title = Toxicity of boric acid, borax and other boron containing compounds: A review| journal = Regul Toxicol Pharmacol |date=2021 | url = https://pubmed.ncbi.nlm.nih.gov/33485927/ | doi = 10.1016/j.yrtph.2021.104873| pmid = 33485927  | last1 = Hadrup | first1 = Niels | last2 = Frederiksen | first2 = Marie | last3 = Sharma | first3 = Anoop K. | volume = 121 }}</ref>

Borax has been in use as an insecticide in the United States with various restrictions since 1946. All restrictions were removed in February 1986 due to the low toxicity of borax, as reported in two EPA documents relating to boric acid and borax.<ref name=EPA.Pest/><ref name=EPA.BoraxOK/>

{{blockquote|EPA has determined that, because they are of low toxicity and occur naturally, boric acid and its sodium salts should be exempted from the requirement of a tolerance (maximum residue limit) for all raw agricultural commodities.<ref name=EPA.Pest />}}

Although it cited inconclusive data, a re-evaluation in 2006 by the EPA still found that "There were no signs of toxicity observed during the study and no evidence of [[cytotoxicity]] to the target organ."<ref name=EPA.Reg62.4/> In the reevaluation, a study of toxicity due to overexposure was checked and the findings were that "The residential handler inhalation risks due to boric acid and its sodium salts as active ingredients are not a risk concern and do not exceed the level of concern", but that there could be some risk of irritation to children inhaling it if used as a powder for cleaning rugs.

Overexposure to borax dust can cause respiratory irritation, while no skin irritation is known to exist due to external borax exposure. Ingestion may cause gastrointestinal distress including [[nausea]], persistent vomiting, abdominal pain, and [[diarrhea]]. Effects on the vascular system and [[human brain]] include headaches and lethargy but are less frequent. In severe cases, a "beefy" red rash affecting the palms, soles, buttocks and scrotum has occurred.<ref name=reig2009/>

The Indonesian Directorate of Consumer Protection warns of the risk of [[liver cancer]] with high consumption of borax over a period of 5–10 years.<ref name=IndonesiaDCP/>

Borax was added to the [[Substance of very high concern|Substance of Very High Concern (SVHC)]] candidate list on December 16, 2010. The SVHC candidate list is part of the [[European Union|EU]] Regulations on the [[Registration, Evaluation, Authorisation and Restriction of Chemicals]] 2006 (REACH), and the addition was based on the revised classification of borax as ''toxic for reproduction'' category 1B under the [[CLP Regulation]]s. Substances and mixtures imported into the EU which contain borax are now required to be labelled with the warnings "May damage fertility" and "May damage the unborn child".<ref name=ECHA2010/> It was proposed for addition to REACH Annex XIV by the [[European Chemicals Agency|ECHA]] on July 1, 2015.<ref name=ECHA2015/> If this recommendation is approved, all imports and uses of borax in the EU will have to be authorized by the ECHA.{{update after|2016|8|17}}

A review of the boron toxicity (as boric acid and borates) published in 2012 in the ''[[Journal of Toxicology and Environmental Health]]'' concluded: "It clearly appears that human B [boron] exposures, even in the highest exposed cohorts, are too low to reach the blood (and target tissue) concentrations that would be required to exert adverse effects on reproductive functions."<ref name=bolt2012/> A draft risk assessment released by [[Health Canada]] in July 2016 has found that overexposure to boric acid has the potential to cause developmental and reproductive health effects. Since people are already exposed to boric acid naturally through their diets and water, Health Canada advised that exposure from other sources should be reduced as much as possible, especially for children and pregnant women.

The concern is not with any one product, but rather multiple exposures from a variety of sources. With this in mind, the department also announced that certain pesticides that contain boric acid, which are commonly used in homes, will have their registrations cancelled and be phased out of the marketplace. As well, new, more protective label directions are being introduced for other boric acid pesticides that continue to be registered in Canada (for example, enclosed bait stations and spot treatments using gel formulations).<ref name=CanHealth2016/>