Dr. R. Michael Kelly of Mid-Michigan Physicians, testifying Monday in a Detroit courtroom, defended himself against accusations he was paid millions of dollars from attorneys representing his patients, who are suing their former employers in asbestos cases, the Detroit Free Press reported.

Under questioning from attorneys representing about 70 defendants, Kelly maintained that asbestos illness is variable and hard to diagnose, saying, "Shortness of breath is subjective. It's like asking what color brown are these walls. Rarely do we have all the data. You have to arrive at decisions with the info you have and proceed with that decision."

Lawyers for the employers have filed a motion with Wayne County Circuit Judge Robert Colombo Jr. to exclude about 80 diagnoses made by Kelly, contending that radiologists have disputed nearly all his X-ray diagnoses, the Free Press reported. The employers also allege Kelly may have misused a machine called a spirometer to measure lung capacity.

If Kelly's testimony is barred, it could leave the former employees scrambling to find another expert to confirm their diagnoses, the newspaper said.