WASHINGTON – A Senate committee is investigating why the Food and Drug Administration long has delayed regulations aimed at increasing safety procedures at hundreds of tissue banks, despite a death last year from infected tissue.

“The repeated delays, combined with FDA’s failure to articulate a coherent rationale for its inaction, are baffling and unacceptable,” Sen. Susan Collins, R-Maine, wrote Wednesday to the agency.

The Government Affairs Committee that Collins chairs has begun investigating the delay and has demanded that the FDA turn over documents that could shed light on why the rules have been more than six years in the making.

FDA officials said they hadn’t seen Collins’ complaint yet, but are working hard to finish the rules.

Donated blood and organs have long been strictly regulated. But other donated tissue – from skin for burn victims to ligaments for knee surgery – are subject to less oversight.

Human tissues can carry diseases, and the way cells are handled can make the difference between a therapy that works or one wasted when the cells die or are contaminated. That risk made headlines a year ago, when a 23-year-old Minnesota man died after receiving infected cartilage during knee reconstruction surgery.

Brian Lykins’ death prompted the FDA to suspend some operations at the nation’s largest tissue supplier, CryoLife Inc., and touched off a federal probe that concluded infections from cadaver tissue used in orthopedic implants are more widespread than previously thought.

The FDA had proposed new regulations for the tissue industry in 1997 that would have set new standards for tissue banking, tightening provisions to prevent such contamination.

But Collins complained that despite the Lykins’ death and congressional prodding, the FDA won’t even say when the proposed rules will be made final.

The FDA’s new chief of biological products, Dr. Jesse Goodman, said Wednesday that finishing the rules is a high priority, but he wouldn’t give a deadline.

The FDA hasn’t been ignoring tissue banks, Goodman stressed. The pending rules aren’t the FDA’s only oversight tool – inspections of tissue banks have more than doubled this year, he added.

But crafting the rules to address such a diverse industry – banks that handle bone face different issues than those handling, say, pancreas cells – has been difficult, Goodman said. “We want to be sure we do this right,” he said.

With 850,000 tissue transplants a year and only a handful of complaints, Goodman said the industry generally is safe.

But he acknowledged that part of the pending regulation is a plan for better reporting of infections so FDA will know actual risk levels – and provisions “that could help improve safety further and potentially prevent other problems from occurring.”