WASHINGTON (AP) — Federal health regulators have found tiny particles of trash in drugs made by biotechnology firm Genzyme. The Food and Drug Administration said Friday that bits of steel, rubber and fiber found in vials of drugs used to treat rare enzyme disorders could cause serious adverse health effects for patients. Shares of Genzyme Corp. dropped $3.12, or 5.9 percent, to $50.05 in afternoon trading. The FDA announcement is the second case of contamination for the Cambridge, Mass.-based company this year. In June, Genzyme was forced to shut down a key production facility due to viral contamination. Calls placed to Genzyme Friday afternoon were not immediately returned. The drugs affected by the latest announcement include: Cerezyme, Fabrazyme, Myozyme, Aldurazyme and Thyrogen. The FDA estimates the contamination only affects about 1 percent of Genzyme's products, and no adverse events have been reported to the government. The agency is not removing the products from the market because it said there are few alternative treatments. FDA regulators say doctors should closely inspect vials for particles before injecting them into patients.