Teachers and staff members at a St. Paul charter school that has faced allegations of financial misdeeds and retaliatory employment practices voted overwhelmingly Wednesday to form a union.

The Community School of Excellence, a magnet for Hmong families over the past seven years, becomes the second unionized charter school in the state.

"This is a historic and positive day for CSE," said Casey Seeling, a CSE kindergarten teacher. "We hope the decision to unionize will increase our student achievement in the future and build stronger relationships among our school community."

The school, located in the former home of St. Bernard's Catholic school in the North End, had 958 students this spring — more than five times the number it had when it opened in 2007. But the past year has seen it contending with controversy surrounding its superintendent, Mo Chang.

In February, Community School of Excellence staff members contacted Education Minnesota, the state's teachers union, about organizing.

The move came while the school and its authorizer, Concordia University in St. Paul, were responding to state Department of Education demands to investigate and resolve claims of federal food-funding misuse and other allegations.

Then, in March, two teachers filed a whistleblower lawsuit claiming they'd been subjected to retaliation and discrimination — allegations the school has denied.

An independent investigation found Chang improperly directed staff members to enter or have students enter lunch codes for meals that were not eaten and encouraged staff to not report suspected cases of child abuse. While some complaints were not supported, the report concluded that Chang had threatened staffers and created an environment where workers were afraid to disagree with her.

Still, the school board fended off Concordia's request to dismiss Chang.

Before Wednesday's vote, Board Chairwoman Patti Hessling said that the school respected its employees' rights to "make a free choice about union representation," but did not believe a union was an answer to the school's challenges.

"We believe that we can achieve best results for our students and our staff by working together directly," Hessling said.

The unionization vote was a "wall-to-wall" vote affecting all employees, including teachers, cooks and education assistants. The school has about 120 staff members.

Earlier this year, 25 teachers at Twin Cities German Immersion School, also in St. Paul, gave 80 percent support to forming a union, making it the state's sole unionized charter school at that time. The state's first charter school, City Academy in St. Paul, was union-represented initially, but no longer is because of a reorganization.

Staff writer Mary Lynn Smith contributed to this report.