Hoping you can tell me, is 0.21 fluoride level bad?

.21 mM(blood) =Bad: Sublethal poisoning occurs at 0.1-0.2 mm Fluoride in blood and lethal poisoning occurs at .2 to .6 mm. (mm = mmol/l = millimoles per liter) a .21 mm concentrations of Fluoride in the blood would likely cause heart failure. The acceptable (mandated in some cities) concentration of Fluoride in the water is 1 milligram per liter or .05 mm.

Fluoride levels: I assume you are referring to the amount of Fluoride in drinking water. The world health organization recommends adjusting the Fluoride levels to a range of 0.5 to 1.0 mg/l (milligrams per liter). These amounts are adjusted according to water consumption in a particular area. Example: desert dwellers tend to drink more water than those in more temperate climates, thus a lower Fluoride content.

In water - safe: The optimum amount of Fluoride in drinking water to protect teeth is 0.7 ppm (mg/l). This is more then 3 times the amount you are asking about. 0.21 ppm of Fluoride in food and drink is not only perfectly safe but will also protect your teeth from tooth decay.