A statistic first cited by a little-known Massachusetts-based online pharmacy became a key point in an argument Senator Clinton made this week in attacking the Bush administration.

The statistic, which refers to the percentage of World Trade Center first responders who have had workers’ compensation claims disputed by insurance companies, appears to have been greatly exaggerated.

The statistic figures in a battle by many New York members of Congress, including Mrs. Clinton and Reps. Carolyn Maloney and Jerrold Nadler, to keep $125 million in federal emergency relief money pledged to help pay for 9/11 responders’ workers compensation claims. The House Appropriations Committee voted this month to rescind the funds, and the full House is expected to vote on the money today. The Bush administration has defended the cuts, arguing that fewer workers’ compensation claims have been received than initially expected.

At a press conference Monday at Red Cross headquarters in Manhattan, Mrs. Clinton said workers’ compensation claims are being “turned down,” or disputed, by insurance companies and employers at 10 times the normal rate. When a claim is disputed, the New York State Workers’ Compensation Board becomes its arbiter.

The “10 times” figure also appeared in a May 31 letter to President Bush signed by Senators Clinton and Schumer and a bipartisan group of 21 New York representatives, and it was cited by Ms. Maloney in a New York Times article.

The figure was derived from a May 17 letter from the vice president of the Injured Workers Pharmacy, LLC, to the WTC Health Effects Treatment Program at Mount Sinai Hospital. The letter reads, “Although IWP routinely deals with disputed workers compensation claims, the ratio of disputed claims for 9/11 victims from the WTC Health Effects Treatment Program is ten times greater than that of our typical patient population.”

According to data provided to The New York Sun by the executive who wrote the letter, Kenneth Barlotta, the actual ratio of disputed claims is significantly less than what was reported in the letter.

Typically, his company reports, the normal rate of disputed claims is between 7% and 8%, but among the 392 September 11-related claims the Injured Workers Pharmacy is handling, 203 are currently disputed. That works out to 51%, or roughly seven times Injured Workers Pharmacy’s normal rate.

Another factor undercutting the credibility of the “10 times” statement is that the Injured Workers Pharmacy has handled only about 3% of the more than 10,000 claims the New York board has received from claimants citing injuries from September 11 and its aftermath.

Information provided by the state Workers’ Compensation Board indicates that, compared to the normal rate, twice as many September 11 responders’ workers’ compensation claims have been disputed. The board reports that the typical rate of disputed claims from 1998 through 2004 is 16%, while the percentage of disputed claims for illness and injury attributed to September 11 is 34%.

Ms. Maloney told the Sun, “Now we have the state admitting that 9/11 injury claims are being challenged at rates far higher than typical claims, and that’s an outrage no one, including the president and members of Congress, should accept.”

Injured Workers Pharmacy is a for-profit, Massachusetts-based workers’ compensation mail-order prescription-drug company founded in October 2001. It provides patients who have filed workers’ compensation claims with prescription drug benefits while acting as an advocate with the patients’ insurance companies. The firm charges the insurance company a fee after the pharmaceuticals claim has been paid.

The Barlotta letter indicates the company has fronted $1.5 million for responders’ claims, approximately $860,000 of which is being disputed by insurance carriers. The letter reads: “While the IWP remains sympathetic to the needs of these victims and the work being done by the WTC Health Effects Treatment Program, the financial strain imposed has become excessive.”

The co-medical director of the Mount Sinai Center for Occupational and Environmental Medicine, Robin Herbert, said that while she could not vouch for the Injured Workers Pharmacy figures, responders “are getting rejected at a disturbingly high rate – that I absolutely agree with.”

The director of public information for the Workers’ Compensation Board, Jon Sullivan, said in an interview that the board was working hard to keep the $125 million in New York. He explained the high rate of challenged WTC claims by saying, “The more complex the issues, the more likely they are to be contested.”