Correction: The article about a referendum on a Montgomery County law that rolled back the expansive collective-bargaining rights of the local police union misspelled the last name of the union’s secretary. She is Jane Milne, not Jane Milner. This version has been corrected.

A referendum has been set for 2012 on a new law that rolled back the expansive collective-bargaining rights of Montgomery County's police union, a county elections official said.

The law, passed unanimously by the County Council in July, took aim at “effects bargaining,” a process that allowed the Fraternal Order of Police to negotiate with county officials not only on wages and benefits but also over day-to-day duties, such as regularly checking e-mail.

In a letter to union secretary Jane Milne on Friday, county Elections Director Margaret Jurgensen verified that the union’s petition for a referendum received enough signatures to place the measure on the 2012 general election ballot. The minimum number required was 30,234 and Milne had 34,828, according to the letter.

Walter Bader, the union president at the time the effects bargaining law was debated, said Monday that the union is pleased with the public support. He said that the group plans to continue to educate voters about the law in an effort to persuade them to strike it down next November.

“With the petition, they’re supporting police officers,” Bader said. “This whole issue has been [caused] by political forces who are just simply opposed to collective bargaining.”

Union officials have said that since its creation in 1982, effects bargaining has had no impact on service to the public. Some police officers fear that the new law allows management to make arbitrary and harmful decisions.

But Montgomery Police Chief J. Thomas Manger and other county officials have said effects bargaining turned basic management decisions into cumbersome and time-intensive battles.

When the bill was introduced, it struck a nerve with the police force. A packed public hearing on the bill in July had some in attendance pleading for understanding while others were shouting in frustration. Many police officers stormed out of the hearing.

Shortly after the bill was passed, the union began work on the referendum petition. The union hired a petition-gathering firm and worked with members and volunteers to collect signatures, Bader said.

County officials and council staff members say they are not surprised by the referendum. Several said they have seen petition organizers gathering signatures at supermarkets in the past few months.

“I was approached by a number of petition gatherers,” said council member Phil Andrews (D-Gaithersburg-Rockville), who pushed for the new law. “When I was approached . . . what was suggested was that traditional collective-bargaining rights were being taken away. This is not a traditional or normal collective-bargaining right by any definition.”

Bader said effects bargaining has led to improved working conditions for police. “It’s a good thing, not an evil,” he said.