* Particles found in less than 1 pct of affected drugs

* Potential for adverse reactions but none reported

* Genzyme shares drop more than 7 percent (Updates with comments from company, analysts, FDA)

By Lisa Richwine and Toni Clarke

WASHINGTON/BOSTON, Nov 13 (Reuters) - Stainless steel fragments, non-latex rubber and fiber-like material have been found in some drugs made by Genzyme Corp (GENZ.O: Quote, Profile, Research), dealing another blow to a company already struggling with manufacturing problems.

The U.S. Food and Drug Administration said in a statement on Friday it had found the foreign particles in less than 1 percent of the products, based on the number of batches tested to date.

The FDA said the objects could cause potentially serious reactions in patients, including blood vessel blockages and life-threatening allergic reactions. So far, no such events have been reported.

Cambridge, Massachusetts-based Genzyme said it has looked through its safety database and found no indication of a problem.

"We have not had any adverse events related to the presence of foreign particles," said Bo Piela, a company spokesman.