General Electric is in a liability fight over a rare and sometimes fatal disease that has been linked to a dye used for MRI scans, with a preponderance of cases involving a GE product called Omniscan.

The disease, nephrogenic systemic fibrosis, or NSF, isn't fully understood, but nearly all cases have involved patients with kidney problems who were injected with MRI contrast agents. In the United States, more than 500 lawsuits have been filed against manufacturers of the drugs, with about 400 of those involving GE.

GE is contesting the lawsuits, saying that it has properly warned of potential risks for some patients, and that there is no proof Omniscan causes NSF. But the company has ignored advice from its own safety experts to restrict the use of the drug, and it has urged the Food and Drug Administration to treat all such agents as equally risky.

The FDA has gone along, despite the findings of two staff doctors that Omniscan is riskier than its rivals. Now, however, an advisory panel has recommended that the agency effectively ban Omniscan and a similar product, Covidien's Optimark, for use on patients with kidney problems.