Fluoride overfeed at a well site near an elementary school in Michigan. (Practical Stuff!).

* Fluoride is a normal constituent of all diets and an essential nutrient.

* Several studies have clearly established a causal relationship between the use of fluoridated water and the prevention of dental cavities.

* Fluoride concentration in unfluoridated water usually ranges from negligible levels to less than 0.3 parts per million (ppm).

* Fluoridated drinking water normally contains 0.7 to 1.2 ppm of fluoride.

* Excessive amounts of fluoride in drinking-water supplies produce adverse health effects and unsightly dental fluorosis (brownish discoloration of teeth).

* Crippling skeletal fluorosis has been observed in parts of the world where the concentration of naturally occurring fluoride in drinking water exceeds 10 ppm.

* This chronic bone and joint disease is characterized by limitation of joint movements, calcification of ligaments, and deformities of bones and joints.

* The disease is extremely rare in the United States.

* Fluoride forms hydrofluoric acid in the acidic environment of the stomach, which in turn causes irritation of the gastrointestinal tract.

* The primary acute health effects of fluorides are sudden onset of nausea, vomiting, cramplike abdominal pain, diarrhea, and pulmonary edema caused by the aspiration of vomitus.

* Ingestion of 5 to 10 grams of sodium fluoride by a 70-kilogram man may cause death.

* A fluoride overfeed occurred at a well site near an elementary school in Michigan.

* The overfeed resulted from two circumstances:

1. a problem in the design of the well system circuit and

2. damage to the logic card that controlled the fluoride solution pump.

* The pump control logic card appeared to have been damaged by an electrical surge or spike.

* As a result, the logic card simulated a situation in which the well pump kept running, and the fluoride solution pump continued to pump solution into the well pump discharge pipe.

* The incident resulted in a high concentration of fluoride (92 milligrams per liter) in water that came from a drinking fountain at the school.

* At least seven students who drank water from the fountain experienced nausea and vomiting.

* It was reported that the water had an unusual taste and was discolored.

* These circumstances may have prevented many of the students from drinking much of the water, thus limiting exposure.

* Vomiting also lowered the extent of incidental exposure.

* The exposure to fluoride was not sufficient to cause any serious adverse health or cosmetic dental effects.

* The exposure was far less than the lethal dose.

* It seems likely that the exposure to fluoride experienced in this incident will not increase the risk of cancer in the exposed children, for the following reasons:

-- The children were exposed to a single low dose of fluoride.

-- Fluoride is a weak carcinogen.