UPDATE 2-U.S. FDA warns Bayer over German plant

* FDA concerned about ingredients used in U.S. products

* Warning follows agency’s March 2009 inspection

* Bayer says it sees no safety or efficacy impact (Adds comment from Bayer spokeswoman)

WASHINGTON, Sept 15 (Reuters) - U.S. health regulators warned Bayer AG BAYG.DE over the testing and quality of pharmaceutical ingredients made at its Bergkamen, Germany, facility, according to a letter released on Tuesday.

The Food and Drug Administration said its concerns arose following a March 2009 inspection that raised questions about the drugmaker’s ability to monitor and test for quality.

“We remain concerned with your released and distributed API batches used in the manufacture of finished products intended for the U.S. market,” the FDA wrote in the letter, dated Aug. 5. API stands for active pharmaceutical ingredients.

Bayer, in an April 2009 written response, said it was taking steps to address the problems. The FDA acknowledged the company was taking corrective steps but said those efforts do “not adequately address some of the deficiencies.”

A Bayer spokeswoman said on Tuesday that the company is analyzing the points raised in the FDA letter as it prepares its response. She added that Bayer’s products undergo a rigorous quality assessment.

“Based on our assessment at this point in time, we have identified no safety and efficacy impact on our products in relation to the (good manufacturing practice) issues as cited by the FDA,” Bayer spokeswoman Rose Talarico said in an emailed statement.

The Bergkamen production site makes ingredients and bulk pharmaceutical chemicals for steroid hormones, according to Bayer’s website.

The FDA's letter can been seen on the Internet at: here (Reporting by Susan Heavey in Washington and Susan Kelly in Chicago; Editing by Tim Dobbyn)