"There's No Fleeing Fleas" (Weekend, September 3), contains some well-meaning but inappropriate advice that could prove dangerous to your readers and their pets. . . (the author's) exterminator "friend" recommends that she "skip the expensive commercial flea powders" when treating her pets for fleas, since "plain old garden Sevin works best." While garden Sevin or carbaryl may do a terrific job in gardens, where it is intended to be used, it may over-do the job on a cat or dog. Depending on the percentage of technical Sevin in the product, and its other active and inert ingredients, a garden Sevin product applied to a family pet could injure or kill the animal, and even adversely affect the owner/applicator.

Pesticides are, after all, poisons, or biologically active compounds intended to control insects, weeds, bacteria and other pests. Used properly, pesticides afford us great benefits in terms of food production, health protection and convenience. However, when you use a pesticide improperly, you (1) violate the law (pesticide misuse is a violation of the Federal Insecticide, Fungicide and Rodenticide Act and subject to civil or criminal penalties), and (2) run the risk of health injury.

I would strongly encourage your readers to purchase pesticide products that have been duly registered by EPA for flea control on dogs or cats, and then apply those products carefully, according to label directions.

EDWIN L. JOHNSON

Director, Office of Pesticide Programs, EPA