Thousands of taxpayers in East Baton Rouge, Livingston and Ascension parishes have until mid-January to decide whether to remain in a class-action lawsuit that alleges the Amite River Basin District collected millions of dollars in unauthorized local property taxes for the Comite River Diversion Canal project.

Jan. 15 is the official “opt-out” date.

Chris Whittington, one of three attorneys appointed to represent the class of taxpayers, said every affected taxpayer will receive notice in the mail of the impending date and an opt-out form. Advertisements also have been put in newspapers, including The Advocate, and notices have been placed at major courthouses in each parish, he said.

Affected taxpayers are automatically members of the class and do not have to opt in, Whittington said. The Jan. 15 deadline applies only to those persons who wish to opt out of the suit, he said.

“As a member of the class you will be bound by any decision held in this case. You do, however, have the opportunity to opt-out of this suit,” reads an ad published Dec. 3 in The Advocate.

“You have the right, if you wish, to have an attorney of your choice present any claim you allegedly have; however, you will be personally responsible for any additional fees and expenses charged by your personal attorney,” the ad states.

“If you opt-out of the class action and fail to take whatever action may be necessary to protect your interests ... you may be forever barred from bringing any action with regard to any claim for the return of the tax dollars at issue in this case,” the ad notes.

Whittington estimated the size of the class at more than 84,000 people.

When Terry Campbell, of the Central area, filed his suit in late 2010, he alleged the Amite River Basin District had collected more than $7.3 million in unauthorized local property taxes for construction of the Comite diversion project.

Whittington said that amount has now climbed to $13 million

The suit says a 2001 agreement between the Amite district and the state required an end to the local tax once property owners provided $6 million for the massive flood-control project. An extra $7.3 million in property taxes was collected, according to the suit.

Dietmar Rietschier, executive director of the Amite River Basin Commission, testified in February that the $6 million figure was the “original estimate’’ for the 10-year duration of the 3-mill tax approved by voters in 2000. Voters in 2010 approved a 10-year extension of the tax at 2.65 mills, he said.

In a recent interview concerning the opt-out date, Larry Bankston, who represents the Amite district commission, said the suit has no merit.

“The tax money is all going toward the project,” he added.

Bankston said an invalidation of the tax would kill the project, on which more than $50 million already has been spent.

“We are proceeding with the (U.S. Army) Corps of Engineers to construct the project,” he said.

Whittington said property owners were required to pay no more or no less than $6 million.

“Period. End of story,” he said. “The court of appeal has ruled on many occasions that we have a case.”

The project, designed to transfer flood waters on the Amite and Comite rivers to the Mississippi River, is expected to cost in the neighborhood of $188 million.

State District Judge Wilson Fields, who is presiding over the case, certified the suit as a class-action.

Opt-out forms must be returned to the following address: Plaintiff’s Steering Committee, 2223 Quail Run Drive, Suite B, Baton Rouge, LA 70808.