WASHINGTON (AP) _ Hundreds of brands of insect repellents, including some types of OFF and Cutter's, are being withdrawn from stores because a long-used ingredient to repel biting flies gave tumors to lab rats and withered their ovaries.

The ingredient's manufacturer, McLaughlin Gormley King Co. of Minneapolis, gave the government test information disclosing the problem and asked that its license to produce and sell it be withdrawn, said Albert Heier, a spokesman for the Environmental Protection Agency.

''The company has voluntarily canceled their registration on this product and informed all the users,'' Heier said Thursday. ''They did the responsible thing.''

Some 200 brands of insect repellent, including Deep Woods OFF and Cutter's, use the ingredient 2,3,4,5-Bis(2,butylene)tetrahydro-2-furaldehyde as an additive to repel flies that bite, Heier said.

Two of the major users of the additive are S.C. Johnson and Son Co. of Racine, Wis., which makes OFF, and Miles Co. of Chicago, producer of Cutter's, Heier said.

Both companies began notifying retailers a couple of weeks ago to take the products containing the ingredient off their shelves. In both cases, the withdrawal affects only a portion of the product line, and does not include every insect repellent the companies make.

S.C. Johnson publicly announced its withdrawal of OFF earlier this month, but Cutter's said nothing in public, although it did notify retailers.

About 25 percent of all insect repellents on the market use the additive, known industrially as R-11 although that name does not appear on the label of any consumer product. The labels, instead, carry the long technical name, Heier said.

The manufacturer's test results showed that the additive caused ''adverse reproductive effects, ovarian atrophy and oncogenicity, or tumors,'' in laboratory rats and mice, the EPA spokesman said.

''These are the preliminary results; the studies aren't completed,'' he said.

The government has done no independent testing of the additive - it requires pesticide manufacturers to conduct safety tests - and does not know how dangerous it may be. The ingredient has been used for 35 years.

''We just don't have enough data to do a risk assessment,'' Heier said. ''We have no evidence that it hurt anybody.''

In the case of Deep Woods OFF, the withdrawal affects about 150,000 cases of aerosol and pump containers and boxes of towelettes, the company said in its public announcement nearly three weeks ago.

Cutter's, however, did not make a public announcement and instead quietly informed retailers to take products from their shelves, said spokeswoman Dionn Tron.

''Because there was no safety reason for doing this, it was simply a precautionary measure on our part, there was no public announcement,'' she said.

The voluntary recall involved several products carrying the Cutter's name, Ms. Tron said. Three Cutter's products did not contain the ingredient in question: the tick repellent, the maximum strength formula and the stick repellent.

The recalled products are being replaced with new ones carrying a yellow sticker saying it is a new formula, the spokeswoman said.

Sixty-five other companies also produce repellents using R-11 under a variety of brand names.

Among those are pet products, including some flea and tick repellents marketed under the Adams or Mycodex brand names, said Linda Kriesman, a spokeswoman for SmithKline Beecham Co.

The products have been reformulated, and those new formulas either have been approved already by the government or are awaiting approval, she said.

People with repellents containing R-11 who want to throw it away should handle its disposal as they would any pesticide in accordance with local ordinances, Heier said.

Ms. Tron said people with Cutter's products containing R-11 can contact the company, which will send a mailer to dispose of it.

However, she said there was no need to get rid of the repellent.

''People who have the stuff can continue to use it,'' she said.