The disclosure of hidden tobacco money in a big study suggesting that lung scans might help save smokers from cancer has shocked the research community and raised fresh concern about industry influence in science.

Two medical journals that published studies by Weill Cornell Medical College researchers in 2006 are looking into tobacco cash and other financial ties that weren’t revealed. The studies reported benefits from lung scans, which the Cornell team has long touted.

It’s a crucial public health issue: Dozens of groups, including such anti-smoking crusaders as the American Cancer Society, have given Cornell money to see whether routinely screening smokers with CT scans can spot the world’s most lethal cancer in time to prevent deaths.

Many were stunned to learn a foundation Cornell set up and listed in the New England Journal of Medicine in 2006 as a study sponsor actually got $3.6 million from a parent company of cigarette maker Liggett Group Inc. The source was reported in the New York Times on Wednesday.

Liggett, whose owner was the first to break with other tobacco companies and say that tobacco was addictive and deadly, announced its donation to the Cornell foundation in 2000 in a press release. But the foundation’s funding source wasn’t disclosed to the journal.

On Wednesday, company spokeswoman Carrie Bloom noted in a statement that the company “had no control or influence over the research.”

Scientists must maintain the trust of patients in research studies, and “any breach of that trust is not simply disappointing but, I believe, unacceptable,” Dr. John Niederhuber, director of the National Cancer Institute, said in a statement.

The chief Cornell researcher, Dr. Claudia Henschke, did not respond to an e-mail requesting comment. Cornell’s dean, Dr. Antonio Gotto, said: “The claim that we set this foundation up in order to cover up the money just isn’t true. We made a public announcement that we were taking the money from the tobacco company.”

Smokers are in dire need of good science on the risk and benefits of lung scans, which are being marketed directly to the public in shopping centers and similar settings. About 1 million people worldwide will be diagnosed with lung cancer this year, and most will die because it is found too late for treatment.

Advanced X-rays called spiral CT scans have been touted as a way to find tumors earlier. But doctors fear that screening could lead to too many false alarms and unnecessary biopsies without saving lives. The cancer society does not recommend them, and most insurers don’t pay for them.

Interest in the scans soared after Henschke published a key study in 1999 saying they found more tumors than conventional X-rays. Her ongoing study aims to prove the value of these scans but has been criticized because it lacks a comparison group.