The state is closing the Union Square T stop during a big festival. Somerville is not so happy.

People looked at a map at the Union Square stop on the Green Line.Vincent Alban For The Boston Globe

What the Fluff?

Somerville business and political officials expressed concern Wednesday after learning the Green Line extension will be shut in September for the second straight year during the popular What the Fluff festival, which draws more than 20,000 people to Union Square.

The Union Square branch line is being closed on Sept. 18 for 25 days to repair the Squires Bridge on McGrath Highway that carries traffic over the Green Line tracks, the state Department of Transportation announced.

The MBTA also closed the line last year during the festival for repairs just months after its grand opening, and this latest closure feels like “another black eye,” said Union Square Main Streets executive director Jessica Eshleman.

“There’s a lot of disappointment and frustration,” Eshleman said. “We did not hear from MassDOT or the MBTA.”

The Fluff festival has been held in September for the last 18 years and is the most popular event in the busy commercial district, Eshleman said. She is urging MassDOT to postpone the bridge work until after the festival or provide shuttle buses for the day of the event.

MassDOT said Wednesday that it is not planning to run shuttle buses during the closure.

A spokesperson for MassDOT did not respond to questions about whether it is considering changing plans, but said: “MassDOT has been engaging frequently with local elected officials and looks forward to continued engagement with local partners. MassDOT is in the process of reaching out to Union Square Main Streets to see how to best support any potential mitigation options. We appreciate all feedback and will take it into serious consideration as we monitor the impacts of the closure.”

The 25-day closure is shorter than originally planned. In June, the MBTA announced the Union Square branch would be closed for 42 days, from July 18 to Aug. 28, for the bridge repairs. After a significant outcry from local officials who were not warned of the closure, the Healey administration reversed course less than a week later, postponing the work until September.

Since the reversal, the project scope, methods, and sequencing were modified to reduce the time to 25 days, MassDOT said.

On Wednesday, MassDOT announced the new time frame for the closure and encouraged riders to take the 86, 87, 91, or CT2 bus routes. Service on all of the suggested alternative bus routes remains below pre-pandemic levels, except on the 86, according to T spokesperson Joe Pesaturo.

Service on the Fitchburg commuter rail line will not be affected, MassDOT said.

State Representative Mike Connolly, who represents parts of Somerville, said he is pleased MassDOT reduced the length of the closure, but has concerns about the impact on the festival. He has a meeting scheduled with MassDOT for next week and plans to advocate for changes.

“We have to ask them to address this, whether that is through the schedule of the project or more dedicated bus transportation,” Connolly said. “It’s definitely an area of concern.”

Somerville Mayor Katjana Ballantyne said she also has a meeting with MassDOT next week.

“MassDOT reached out, told us that they were reducing it from 42 days to 25 days, and said we want to meet with your team and want to hear what your concerns are,” Ballantyne said. “That meeting hasn’t happened yet.”

It was not clear Wednesday why the deteriorated bridge was not fixed before the long awaited Green Line extension opened for passenger service in March 2022. A MassDOT spokesperson noted that the construction of the extension was managed by the administration of former governor Charlie Baker.

Highway Administrator Jonathan Gulliver, who was in charge of the department during the last phases of Green Line extension construction under Baker, said the new 25-day schedule to repair the bridge will minimize the impacts to transit service. The Squires Bridge carries around 40,000 cars per day, MassDOT said, while around 1,550 riders board the Green Line at Union Square each weekday.

“We know this will come as an inconvenience to Green Line riders and we have worked to adjust our construction schedule to minimize as much as possible while balancing the need to complete necessary infrastructure work,” Gulliver said in a statement.

Another segment of the Green Line, between North Station and Government Center Station, will also close for 25 days starting on Sept. 18, according to the MBTA, to allow for the continued demolition of Government Center Garage by a private developer. The MBTA will not provide shuttle buses.

The Union Square closure won’t impact the other branch of the Green Line extension, which runs to Medford.

The announcement came just two days after Transportation Secretary Gina Fiandaca announced she is resigning from the top MassDOT position on Sept. 11. Why Fiandaca is leaving after less than eight months — or where she may be going — remains unclear.

MassDOT will hold an information session for impacted Green Line riders at the Central Somerville Public Library on Sept. 12 at 6:30 p.m., the agency said.