Some scientists are disputing a decision to link 50 kinds of cancer to exposure to World Trade Center dust.
The experts say that there's little research to prove that exposure to the toxic dust on Sept. 11 caused even one kind of cancer.
The head of the National Institute for Occupational Safety and Health added scores of common and rare cancers to a list this month.
The decision could help hundreds of people get payments from a multibillion-dollar World Trade Center health fund to repay those sickened after the 9/11 terror attacks.
Some experts say there is little research to prove that breathing the toxic dust gave people cancer.
Others say the contaminants may well have triggered or accelerated some types of cancers, and that the government made a choice that serves a large human need.