Filed at 6:34 p.m. ET

WASHINGTON (AP) -- The American Red Cross recalled thousands of pints of blood products shipped to hospitals in 2000, federal documents show, and some possibly hazardous blood was transfused into patients before word reached doctors not to use it.

Recalls were up 18-fold from 12 years earlier.

Consumer advocates cited the 641 recalls -- and federal documents suggesting it's unclear whether anyone has gotten sick from tainted blood -- in urging Congress Thursday to investigate the safety of blood provided by the Red Cross.

Senate Majority Leader Tom Daschle and Sen. Edward Kennedy called the allegations serious, and Kennedy agreed to look into them.

``The disclosures ... raise serious questions about the ability of the American Red Cross to ensure the safety of its blood supply,'' said Kennedy, D-Mass. ``Congress needs to deal with these questions, too, and take whatever steps are necessary to guarantee the safety of the blood supply.''

None of the recalls were Class 1, FDA's designation for the most dangerous type. Most were Class 2 recalls, meaning there was a small risk that patients could be harmed.

It is the latest black eye for the Red Cross, which provides 45 percent of the nation's blood and is fighting government regulators in federal court over this very issue.

The Food and Drug Administration has accused the Red Cross of repeated and serious violations of blood safety regulations, including shipping contaminated blood, despite a 1993 court order mandating improvements. Last month, the FDA has asked a federal judge to hold the charity in contempt of court and allow the government to levy millions of dollars in fines for continuing violations.

That court fight promises to last months. The consumer group Public Citizen wrote Daschle and Kennedy Thursday that congressional intervention would speed solutions.

``Force the Red Cross to improve its public health-threatening record,'' the group wrote.

The Red Cross argues it has spent millions improving its blood business and that the blood supply is safer than ever.

``It is unfortunate the Public Citizen is creating unnecessary fear and alarm about the safety of the blood supply,'' said Red Cross interim general counsel Larry Moore. ``The chief priority of the Red Cross is to ensure that patients who depend upon blood receive the safest possible products.''

FDA court documents say Red Cross recalls of blood jumped from 36 in 1988 to 641 in 2000. Those latest recalls totaled 12,701 units of blood products, including red blood cells and platelets.

One example involves cytomegalovirus, which doesn't harm most healthy adults but can kill or seriously injure the ill or newborns. In October 2000, the Red Cross recalled four units of blood labeled CMV-free when in fact they hadn't been tested -- and three already had been transfused, say the FDA documents.

The Red Cross argues that no one has been found to have been harmed by its mistakes.

That is ``a notoriously dangerous assumption to make,'' FDA blood chief Dr. Jay Epstein said in court documents. It is very hard to detect transfusion-caused illnesses because some infections lie dormant for a long time and doctors aren't required to report suspicious infections to the government, he said.

Thursday's allegations are the latest public blow to the Red Cross. It had to backtrack from a sharply criticized plan to divert to other uses some of the half-billion dollars donated to help victims of the Sept. 11 terrorist attacks. And the Red Cross provoked tension with other blood banks seeking massive donations following Sept. 11, even after it became clear supplies were sufficient. The Red Cross wound up discarding 49,000 units of donated red cells.