WASHINGTON - Consumers should stop using Zicam Cold Remedy nasal gel and related products because they can permanently damage the sense of smell, federal regulators said yesterday.

The over-the-counter products contain zinc, an ingredient that scientists say may damage nerves in the nose needed for smell. The other products affected by the Food and Drug Administration's announcement are adult and kid-size Zicam Cold Remedy Nasal Swabs.

The FDA says about 130 consumers have reported a loss of smell after using Matrixx Initiatives' Zicam products since 1999. Shares of the Scottsdale, Ariz.-based company plunged to a 52-week low after the FDA announcement, losing more than half their value.

"Loss of the sense of smell is potentially life threatening and may be permanent," said Charles Lee, of the FDA's compliance division. "People without the sense of smell may not be able to detect dangerous life situations, such as gas leaks or something burning in the house."

Matrixx defended its products' safety but said it may remove them from sale.

In January 2006, the company agreed to pay $12 million to settle lawsuits involving 340 plaintiffs, The Inquirer reported.

The firm then admitted no wrongdoing and a spokesman called the settlements "strictly a business decision."

The FDA said this week that Zicam Cold Remedy was never formally approved because it is part of a small group of remedies, called homeopathic products, that are not required to undergo federal review before launching.

A warning letter to Matrixx yesterday asked the company to stop marketing its zinc-based products, but the agency did not issue a formal recall. Instead, regulators said Matrixx would have to submit safety and effectiveness data.

The agency is requiring formal approval now because of the product's safety issues.

"It won't bring my smell back, but at least I feel like there's some justice that's starting to take place," said David Richardson of Greensboro, N.C., who lost his sense of smell after taking Zicam for a cold in 2005. He said he hoped the product would be formally banned.

Matrixx has settled hundreds of lawsuits connected with Zicam in recent years but says on its Web site: "No plaintiff has ever won a court case, because there is no known causal link between the use of Zicam Cold Remedy nasal gel and impairment of smell."

The company said in a statement yesterday that the safety of Zicam Cold Remedy was "supported by the cumulative science."

But FDA scientists say they are unaware of any data supporting Zicam's labeling, which says the drug reduces cold symptoms.