(The Hill) — The union representing thousands of Starbucks workers has said it will launch its “largest strike ever” on Thursday amid the coffee chain’s annual Red Cup Day.

Starbucks Workers United said in a press release on Monday that it is demanding the company bargain over staffing and scheduling issues and turn off mobile ordering on promotion days like Red Cup Day.

The yearly event, during which Starbucks gives away free reusable holiday cups, is the company’s “biggest sales event of the season” and “one of the most infamously hard, understaffed days for the baristas that work them,” according to the union.

Promotion days like Red Cup Day produce a “flood of customers” but are not paired with any additional staffing, Starbucks Workers United said.

“Starbucks is creating unnecessarily stressful working conditions by scheduling promotion after promotion without increasing staffing,” Neha Cremin, a barista in Oklahoma City, said in a statement. 

“Understaffing hurts workers and also creates an unpleasant experience for customers,” Cremin continued. “Starbucks has made it clear that they won’t listen to workers, so we’re advocating for ourselves by going on strike.” 

Starbucks workers reportedly filed an unfair labor practice charge with the National Labor Relations Board (NLRB) earlier this fall over the coffee chain’s refusal to bargain over promotion days.

Administrative law judges have repeatedly found Starbucks in violation of federal labor laws over the past year. The company had lost 22 cases before the National Labor Relations Board (NLRB) as of August, according to Bloomberg Law.

In late September, an NLRB judge also ruled that Starbucks broke the law by providing raises and additional benefits to non-union workers without offering those same increases to unionized staff.

However, Starbucks said in a statement that Workers United has not agreed to meet for bargaining in more than four months.

“As we join together to uplift the holiday season and reflect on the past year, we again call on Workers United to fulfill their obligations and engage in the work of negotiating first contracts on behalf of the partners they represent,” the company said.

“Starbucks remains ready to progress in-person negotiations with the unions certified to represent partners,” it added.

While the coffee chain also recently announced its plans to raise hourly wages by 3 percent, it has still faced pushback from workers. Alex Yaeger, a barista in Albany, N.Y., called the move “tone deaf” in the wake of the company’s recently reported fourth-quarter revenue. 

“This is exactly why we are fighting for a union,” Yaeger said in a statement. “As our sisters and brothers at the UAW proved so powerfully, record profits should mean record contracts. And that’s why we’re continuing to organize.”

The United Auto Workers (UAW) union secured major gains last month — including a 25 percent pay raise, cost-of-living adjustments and a more rapid progression to the top wage rate — after striking against the Big Three automakers for more than six weeks.

Hollywood writers and actors also brought the industry to a standstill for six months this year with their dual strikes. While the Writers Guild of America (WGA) struck a deal with the major film and television studios in September, SAG-AFTRA remained on strike until reaching an agreement with studios last week.