Less than a week before the long-awaited hearing scheduled for Wednesday at 9:30 a.m., the high court agreed to hear Dow's appeal of the medical monitoring facet of the suit. It also ordered circuit court proceedings to stop while the matter is under consideration.

Dow's briefs in support of its appeal are due in late July, the plaintiffs will be expected to reply by late August. The Supreme Court is likely to schedule an oral hearing on the topic within 30 days of reviewing the parties' documents.

The stay order by the court marks the sixth delay of a hearing to determine if the two-issue suit filed in March 2003 should be certified as a class.

More than 160 plaintiffs are seeking the value of their property, which they say has been made worthless by dioxin contamination deposited by Dow into the river and onto the flood plain. They also want Dow to fund a trust to monitor their health, which they believe has been jeopardized by exposure to the dioxin.

Class designation would mean more than 2,000 property owners and unknown number of people who have lived along the flood plain since January of 1984 could join.

Dow spokesman Scot Wheeler said the company is pleased the court will consider the medical monitoring matter before the case proceeds.

"It makes sense to resolve this issue and then let parties focus on the rest of the case," Wheeler said. "It saves the time, the resources and the burden on the court."

If the Supreme Court was to dismiss the medical monitoring claim, the second proposed class of residents, the ones who may or may not still live on the flood plain, could not proceed.

Dow attorneys say medical monitoring is not a valid claim in Michigan. They insist that compensation can only be sought for injuries that exist, not for those that might occur later. They say plaintiffs have not claimed that they have been told by a medical professional that they have or will suffer injury, or have even had testing to determine if dioxin levels exist in their bodies.

Saginaw County Circuit Court Judge Leopold Borrello disagreed with Dow's argument in August when he said that while Michigan law doesn't allow such claims, it doesn't disallow them either.

No record has been developed, and plaintiffs should be given the opportunity, he said.

In October, the Michigan Court of Appeals said it would not hear Dow's appeal of that ruling.

Borrello has said that he wishes to move the case forward, and refused further delays of the class hearing. He was not available for comment on the Supreme Court development Friday.

Teresa Woody, an attorney on the legal team representing plaintiffs, said the group plans to ask the Supreme Court Monday to reconsider its decision to delay court proceedings for the property damage portion of the suit, but said the decision to the hear the appeal now was not unexpected.

"That's going to happen at some point anyway," she said, noting that either party was likely to appeal a final ruling by the Circuit Court.

The plaintiffs believe that since they were exposed to dioxin, they will have to have their health checked routinely in the future for potential latent health effects.