IDENTIFICATION AND USE: also known as (sodium borate decahydrate; sodium pyroborate; birax; sodium tetraborate decahydrate; sodium biborate) is a natural mineral compound (Na2B4O7 • 10H2O). It was discovered over 4000 years ago.

Borax is usually found deep within the ground, although it has been mined near the surface in Death Valley, California since the 1800s. Although it has numerous industrial uses, in the home borax is used as a natural laundry booster, multipurpose cleaner, fungicide, preservative, insecticide, herbicide, disinfectant, dessicant, and ingredient in making ‘slime’.

Borax crystals are odorless, whitish (can have various color impurities), and alkaline. Borax is not flammable and is not reactive. It can be mixed with most other cleaning agents, including chlorine bleach. Borax may also be used as an insecticide to kill roaches, ants, and fleas. In fact, it is also toxic to people.

HUMAN EXPOSURE/TOXICITY: repeated exposure of a hair preparation containing 3.2% sodium borate and a cleansing cream containing 1.7% sodium borate on the skin of 12 and 14 subjects, respectively. The test material was applied under an occlusive patch to the backs of subjects daily for 21 consecutive days. Sites were scored one hour after patch removal. Applications 4 to 21 of the hair preparation produced erythema and papules in most subjects; the total cumulative irritancy score was 571 (maximum =630). The cleansing cream caused slight erythema in two subjects only, resulting in a total irritancy score of 6.4. The investigators concluded that, under the condition of the study, the hair preparation was a “mild to moderate” cumulative irritant, whereas the cleansing cream was practically nonirritating.

The Kligman maximization procedure was used to study the sensitizing potential of a hair preparation containing 3.2% sodium borate in 25 subjects. The material was initially applied under a 48 hr patch to each subject to determine whether sodium lauryl sulfate (SLS) pretreatment was required. The test material was found to be irritating; it was determined that SLS treatment was unnecessary. The undiluted hair preparation was applied under occlusion to one arm of each subject for 48 hr. This procedure was repeated every other day for 10 days (5 application). 10 days after removal of the fifth induction patch, a 48 hr occlusive challenge patch was applied to a fresh site. Sites were scored at 48 and 72 hr. The hair preparation containing 3.2% sodium borate induced no irritation during challenge phases of the test; this product was determined to be nonsensitizing when applied to human skin.

Two cleansing creams, each containing 1.7% sodium borate, were assayed in panel tests. In each study, panelists were given the product and asked to use it daily for 2 weeks. In a group of 100 subjects, one cream produced no irritation. In the other panel, which included 90 subjects, there was one report of irritation; a subject accidentally instilled some of the cream into her eyes. A stinging sensation was experienced; however, the irritation subsided following eye rinse.

CASE REPORTS: Seven patients with brain tumors who were receiving neutron-capture therapy were administered iv 18.6 to 27.3 g of sodium borate (a range of 32-50 mg/kg/of boron). In this procedure the boron served as the capture element. A consistent hypoxic type of ECG abnormality was observed immediately after the injection. When the boron was rapidly excreted or when the dose of boron was <50 mg/kg, the ECG returned to normal within 24-48 hr. The researchers suggested that the entrance of boron into myocardial cells in appreciable concentrations produced injury resulting in cell hypoxia.

A case-series report of seven infants (aged 6-16 weeks) who used pacifiers coated with a borax and honey mixture for 4-10 weeks concluded that exposures ranged from 12 to 90 g, with a very crudely estimated average daily ingestion of 18-56 mg of boron per kg of body weight. Toxicity was manifested by generalized or alternating focal seizure disorders, irritability, and gastrointestinal disturbances. Although infants appear to be more sensitive than adults to boron compounds, lethal doses are not well documented in the literature.

Ten patients receiving neutron-capture therapy were administered iv doses of sodium borate up to 20 g (2.12 g boron). The median dose was 25 mg/kg boron and the maximum dose was 46 mg/kg boron. The patients received 1-4 doses at intervals of 2 weeks to 3 months. The immediate symptoms were: intense gastrointestinal stimulation leading to nausea, vomiting, urgent defecation and diarrhea, “mild peripheral vascular collapse”, mild mental confusion, and a flushed skin on the face. Later symptoms were: drowsiness, lethargy, and continued gastroirritability. These effects ceased by days 3-5 and no deaths occurred. Toxic effects were not enhanced by up to 4 successive iv administrations.

ADVERSE EFFECTS: chronic eczema. Long-term exposure to borax dust may lead to inflammations of the mucous membranes of the airways (bronchitis, laryngitis) and to conjunctivitis. Ingestion of 5 to 10 g by young children can cause severe vomiting, diarrhea, shock and death. Effects from ingestion include: abdominal pain, diarrhea, headache, nausea, vomiting, weakness, convulsions. Acute oral ingestion of 2 to 20 grams or more of boric acid can result in symptoms that include nausea, vomiting, abdominal pain, diarrhea, depression of the central nervous sytem, and convulsions. Subacute or chronic doses of boric acid may result in signs and symptoms including dermatitis, loss of appetite, nausea, and vomiting. In the occupational setting, exposures to airborne boric acid and borax dusts have been shown to be irritating to the respiratory tract and the eyes of workers. These symptoms for both acute and chronic exposures, include eye irritation; dryness of mouth, nose, or throat; sore throat; and productive cough.

Peripheral blood cultures were exposed to various doses (5 to 500 mg/L) of boron compounds. Sister-chromatid exchange, micronucleus and chromosomal aberration tests were applied to estimate the DNA damage, and biochemical parameters (superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glucose-6-phosphate dehydrogenase, total glutathione, malondialdehyde and total antioxidant capacity) were examined to determine oxidative stress. According to /these/ findings, various boron compounds at low doses were useful in supporting antioxidant enzyme activities in human blood cultures. It was found that the boron compounds do not have genotoxic effects even in the highest concentrations, though in increasing doses they constitute oxidative stress. It is concluded that the tested boron compounds can be used safely, but it is necessary to consider the tissue damages which are likely to appear depending on the oxidative stress.

The effect of borax on human chromosomes was analyzed in this study. Venous blood from 30 male students at Thammasat University, Thailand (age 18-25 years) was collected for lymphocyte cell cultures. This experiment was divided into two groups: the first group was the control group and the second group was the experimental group. The lymphocyte cells in the control group were cultured without borax. The experimental group was divided into four subgroups. The lymphocyte cells in each experimental subgroup were cultured with different concentrations of borax (0.1 mg/mL, 0.15 mg/mL, 0.2 mg/mL and 0.3 mg/mL). Human chromosomes were studied for abnormalities through Giemsa-staining and G-banding. The results show that the numbers of metaphase plates (the metaphase plate which contained 46 chromosomes; 46, XY) and metaphase chromosomes were reduced when lymphocyte cells were cultured with 0.15 mg/mL (57.2%), 0.2 mg/mL (50.8%) and 0.3 mg/mL (42.3%) concentrations of borax. There was a statistically significant difference between the control and experimental subgroups (p < 0.05). Sister chromatid separation was found in the 0.3 mg/ml borax concentration experimental subgroup. This shows that borax (at 0.15, 0.2 and 0.3 mg/mL concentrations) affects the cell and human chromosomes (both numerical and structural abnormalities). Borax may cause human chromosome abnormalities and lead to genetic defects.

OTHER TOXICITY INFORMATION: autopsies have revealed hepatitis, nephrosis and cerebral edema. In some cases autopsies have revealed, necrotic changes in intestines, plethora of internal organs, brain tissue stasis and pulmonary edema. Fatal doses for humans are variously estimated to be 5 to 6 g for children and 10 to 25 g for adults. Borax and boric acid used in powders and ointments have resulted in serious poisonings and death.