http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4090869/ [quote]Toxicity[edit]
Main article: Fluorine-related hazards
A diagonal placard with warning poison
A diagonal placard with warning corrosive
A diagonal placard with warning inhalant
A diagonal placard with warning oxidant
U.S. hazard signs for commercially transported fluorine[249]
Elemental fluorine is highly toxic to living organisms. Its effects in humans start at concentrations lower than hydrogen cyanide's 50 ppm[250] and are similar to those of chlorine:[251] significant irritation of the eyes and respiratory system as well as liver and kidney damage occur above 25 ppm, which is the immediately dangerous to life and health value for fluorine.[252][253] Eyes and noses are seriously damaged at 100 ppm,[252] and inhalation of 1,000 ppm fluorine will cause death in minutes,[254] compared to 270 ppm for hydrogen cyanide.[255]
Hydrofluoric acid[edit]
left and right hands, two views, burned index fingers
Hydrofluoric acid burns may not be evident for a day, after which calcium treatments are less effective.[256]
See also: Chemical burn
Hydrofluoric acid is a contact poison with greater hazards than many strong acids like sulfuric acid even though it is weak: it remains neutral in aqueous solution and thus penetrates tissue faster, whether through inhalation, ingestion or the skin, and at least nine U.S. workers died in such accidents from 1984 to 1994. It reacts with calcium and magnesium in the blood leading to hypocalcemia and possible death through cardiac arrhythmia.[257] Insoluble calcium fluoride formation triggers strong pain[258] and burns larger than 160 cm2 (25 in2) can cause serious systemic toxicity.[259]
Exposure may not be evident for eight hours for 50% HF, rising to 24 hours for lower concentrations, and a burn may initially be painless as hydrogen fluoride affects nerve function. If skin has been exposed to HF, damage can be reduced by rinsing it under a jet of water for 10–15 minutes and removing contaminated clothing.[260] Calcium gluconate is often applied next, providing calcium ions to bind with fluoride; skin burns can be treated with 2.5% calcium gluconate gel or special rinsing solutions.[261][262][263] Hydrofluoric acid absorption requires further medical treatment; calcium gluconate may be injected or administered intravenously. Using calcium chloride – a common laboratory reagent – in lieu of calcium gluconate is contraindicated, and may lead to severe complications. Excision or amputation of affected parts may be required.[259][264]
Fluoride ion[edit]
See also: Fluoride toxicity
Soluble fluorides are moderately toxic: 5–10 g sodium fluoride, or 32–64 mg fluoride ions per kilogram of body mass, represents a lethal dose for adults.[265] One-fifth of the lethal dose can cause adverse health effects,[266] and chronic excess consumption may lead to skeletal fluorosis, which affects millions in Asia and Africa.[266][267] Ingested fluoride forms hydrofluoric acid in the stomach which is easily absorbed by the intestines, where it crosses cell membranes, binds with calcium and interferes with various enzymes, before urinary excretion. Exposure limits are determined by urine testing of the body's ability to clear fluoride ions.[266][268]
Historically, most cases of fluoride poisoning have been caused by accidental ingestion of insecticides containing inorganic fluorides.[269] Most current calls to poison control centers for possible fluoride poisoning come from the ingestion of fluoride-containing toothpaste.[266] Malfunctioning water fluoridation equipment is another cause: one incident in Alaska affected almost 300 people and killed one person.[270] Dangers from toothpaste are aggravated for small children, and the Centers for Disease Control and Prevention recommends supervising children below six brushing their teeth so that they do not swallow toothpaste.[271] One regional study examined a year of pre-teen fluoride poisoning reports totaling 87 cases, including one death from ingesting insecticide. Most had no symptoms, but about 30% had stomach pains.[269] A larger study across the U.S. had similar findings: 80% of cases involved children under six, and there were few serious cases.[272]