The toxicity of an element depends on what other elements it is bonded to.

PURE BORON & BORON OXIDE:
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Boron, as well as borates (boron oxide), are poisonous and are used in pesticides and are known to be toxic to plants. The EPA allows no more than 30 parts of boron per million parts of cottonseed oil (30 ppm) and 8 ppm of boron in or on citrus fruits. The EPA requires that discharges or spills into the environment of 100 pounds of more of boron trichloride and boron trifluoride be reported. The Occupational Safety and Health Administration (OSHA) has set an occupational exposure limit of 15 milligrams per cubic meter (15 mg/m3) for boron oxide dust in workplace air for an 8-hour workday, 40-hour workweek. The National Institute for Occupational Safety and Health (NIOSH) currently recommends an occupational exposure limit of 10 mg/m3 for boron oxide dust. NIOSH also recommends that 25 ppm boron trifluoride be considered immediately dangerous to life and health. This is the exposure level of a chemical that is likely to cause permanent health problems or death. The Food and Drug Administration (FDA) allows no more than 310 ppm of boron as a food additive.

SODIUM BORATE (BORAX):
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Used as fertilizer or hydroponic nutrient, and as a component in laundry detergent. Can be fatal if swallowed. Fatal doses for humans are estimated to be 5-6 grams for infants and 10-25 grams for adults. Dusts or spray solutions may irritate eyes. Not rapidly absorbed through intact skin or mucous membranes. Penetration will rapidly occur through open wounds, burned skin and areas of active dermatitis if exposed to powder or strong aqueous solutions. Exposure to dust or spray solution may cause acute irritation, which may worsen with increased temperature. Symptoms include nasal irritation, couching and some chest discomfort.

SODIUM BOROHYDRIDE:
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Inhalation produces damaging effects on the mucous membranes and upper respiratory tract. Symptoms may include irritation of the nose and throat, and labored breathing. May cause lung edema, a medical emergency. Swallowing can cause severe burns of the mouth, throat, and stomach. Can cause sore throat, vomiting, diarrhea. Severe irritation or skin burns can result from contact with wet material or contact by moist skin. Contact can cause blurred vision, redness, pain and severe tissue burns. Supports combustion. Flammable solid. Can ignite in air from an open flame, continuing to burn as hydrogen is evolved. It reacts with water or steam to produce flammable hydrogen. An explosion can occur by spontaneous ignition of the gases released from a saturated solution of sodium borohydride in dimethylformamide at 17C.

SODIUM BOROHYDRIDE IN SODIUM HYDROXIDE-BUFFERED WATER SOLUTION
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Non-flammable. Non-toxic. Contact with platinum group metal catalyzes release of hydrogen with associated flammability and safety concerns.

Compared with....

TOXICITY OF AUTOMOTIVE GASOLINE
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