ABSTRACT: Thirty-four persons became ill with acute fluoride poisoning shortly after drinking water in an elementary school in Los Lunas, NM. The water supply of the school was supplemented with a concentrated sodium fluoride solution designed to raise fluoride levels in drinking water to 1 to 5 ppm. Two water samples taken after the incident was reported showed elevated fluoride levels of 375 and 93.5 ppm. Malfunction