MINNEAPOLIS (AP) — A judge on Wednesday blocked AT&T’s plan to build a 450-foot cellphone tower near the edge of the Boundary Waters Canoe Area, ruling that the proposed tower with its flashing airplane safety lights would likely hurt the “scenic and aesthetic resources” of the pristine northeastern Minnesota wilderness.

But Hennepin County District Judge Philip Bush ruled that a smaller, unlighted tower of up to 199 feet would be acceptable.

Bush, who heard the lawsuit last April, sided with the Friends of the Boundary Waters Wilderness. The group argued that the 450-foot tower’s flashing lights would be visible from several lakes and waterways within the BWCA, an area covering more than 1 million acres with more than 1,000 lakes and hundreds of miles of streams and rivers.

Paul Danicic, executive director of Friends of the Boundary Waters Wilderness, called the ruling “a major victory for the hundreds of thousands of people who visit the Boundary Waters every year, and for the wilderness’s scenic vistas and wildlife.”

“We hope AT&T will pursue without further delay a tower plan that expands cell service in the area for local residents, while preserving the most popular wilderness area in the country,” Danicic said in a news release.

AT&T Mobility LLC contended that one tall tower would do the best job of extending cellphone service east of Ely and allowing paddlers in remote areas to call for help in emergencies. The phone company said there was no good alternative to the 450-foot tower, and lawyers for AT&T wrote in a pretrial filing that improved wireless coverage “could literally make the difference between life and death” for BWCA visitors.

At issue was whether the 450-foot tower would violate the Minnesota Environmental Rights Act (MERA), which lets citizens sue to protect natural resources that are in danger of being impaired. The judge ruled that the larger tower would violate the law but that a smaller tower would not. He rejected AT&T’s argument that improved cell service is needed within the BWCA for public safety.

Bush found that a 450-foot tower would have “a qualitative and severe adverse effect on the scenic views from at least 10 significant areas” within the BWCA, which was established by federal law in 1964 and sits on Minnesota’s border with Ontario.

The proposed site is near Fall Lake in Lake County, just more than a mile outside the BWCA boundary. The tower would sit on a 150-foot-high ridge, lifting it about 600 feet over most of the surrounding landscape. Federal Aviation Administration regulations would require the tower to have flashing lights around the clock.

The Friends of the Boundary Waters Wilderness also argued that a tall tower would pose a threat to birds ranging from eagles to warblers. A shorter tower would not need lights or guy wires that would endanger birds. Bush found the proposed tower would kill protected migrating songbirds and threatened peregrine falcons. But since it’s difficult to determine how many birds would be killed, he said that factor — while weighing against construction of the 450-foot tower — was less strong than other factors.

AT&T had already started construction preparations when Friends filed its lawsuit in June 2010, but agreed to suspend work while the case is pending. The Lake County Board approved the tower in February 2010 as a way to improve cellphone coverage.

AT&T spokesman Marty Richter said Wednesday the company is reviewing the ruling and considering its options.

“We continue to believe the county’s well-considered decision to approve this important public safety facility was correct,” Richter said in a statement.