NEW YORK - More than 1,600 people who filed lawsuits contending that their health was ruined by dust and smoke from the collapsed World Trade Center must decide by next Monday whether to keep fighting in court, or drop the litigation and apply for benefits from a government compensation fund.

For some, the choice is fraught with risk.

Federal lawmakers set aside $2.76 billion last winter for people who developed illnesses after spending time in the ash-choked disaster zone.

But to be considered for a share of the aid, all potential applicants must dismiss any pending lawsuits by the deadline and forever give up their right to sue over 9/11 health problems. Anyone with a suit still pending Jan. 3 is barred from the program for life.

The government program does not require sick people to prove that their illness is related to 9/11. But applicants will not know for months, or even years, how much money they might eventually receive from the program. That means some people may give up their lawsuits and find out later that they qualify for only a modest payment.

Others face a deeper problem. People exposed to trade-center dust have blamed it for hundreds of illnesses, but the fund covers only a limited number of ailments, including asthma, scarred lungs, and other respiratory problems. It does not include any type of cancer, which scientists have yet to link to trade-center toxins.

But the possibility that cancer could someday be covered has led some plaintiffs to drop their suits anyway.

"I've weighed my options and rolled the dice believing that the country I helped is not going to let me down," said former New York City police detective John Walcott, who retired after being diagnosed in 2003 with acute myelogenous leukemia.

He decided a few days before Christmas to drop his case, saying he had come to believe he would never get anything out of the legal system.

"The court system was set up for attorneys to make a lot of money," he said. He added that at age 47, he is tired of a court fight that had no end in sight. "I'm done with 9/11. I can't go forward with my life and family and live in peace with this hanging over me."

The special master overseeing the compensation fund, Sheila Birnbaum, acknowledged that the deadline would present some people with a hard choice, especially if they have an illness that the fund does not cover.

"That is one of the dilemmas," she said.

Birnbaum noted that the law gives her no latitude. Anyone with a lawsuit active on Jan. 3 will be disqualified from consideration, she said, even if the person's illness is later deemed to be covered.

"It's a hard decision that they have to make," she said.

The long application process for the fund began in October, and Birnbaum said she expected thousands to apply. She could not say how many might do so by the time the fund closes years from now.

Lawyers representing people with pending cases said they have been going over the pros and cons with their clients for several months.

"It's a complicated analysis," said lawyer Gregory Cannata, whose firm represents about 100 people, including laborers who were brought in to repair damaged buildings and cleaners who swept tons of dust from office suites.

For the most part, Cannata said, his clients have decided to stick with their lawsuits, in part because of the possibility of a larger payout than they might receive under the government program.

Police officers, firefighters, and city contractors who cleared away the 9/11 rubble make up only a small fraction of those facing the dilemma. Most of the more than 5,000 city workers who sued alleging that the city had failed to protect them from the dust settled their cases in 2010, before the fund was created.

Walcott, the retired police detective, was one of a few who rejected the deal, worth more than $700 million. Under the law, people who settled previously will be allowed to apply for government benefits. Any award they receive will be reduced by the amount they got from the legal settlement.

The tough decisions will not end Jan. 2. Besides people with pending legal claims, thousands more New Yorkers have become ill, perhaps because of exposure to the dust. They will have to decide in the coming years whether to sue someone over their illness or apply to the government program.

If too many people apply for aid from the compensation fund - including those with common illnesses that may or may not have anything to do with 9/11 toxins - the $2.76 billion set aside by Congress may be exhausted quickly. Noah Kushlefsky, a lawyer with the firm Kreindler & Kreindler, said that adding just 1,000 people with cancer to the program could cost $1 billion.