CNN Business  — 

Workers who provide food and drinks to travelers at San Francisco International Airport are on strike, seeking what they say would be their first raise in four years.

The 1,000 strikers are members of Unite Here Local 2, a Bay Area union with 15,000 members. The airport workers work under a multi-employer joint labor agreement that covers 30 different employers spread among 84 different locations at the airport.

“Passengers should bring their own food and grab coffee before arriving at SFO,” said Anand Singh, president of the union, who said the union has been in negotiations for nine months.

“Almost all of SFO’s food and beverage outlets are closed. Workers are tired of jobs that aren’t enough to live on, and we’re prepared to strike for as long as it takes to win better wages and affordable health care.”

The negotiating team for the restaurants did not immediately reply to a request for comment Tuesday. Airport management, which is not a party to the talks, issued a statement apologizing to passengers for any inconvenience.

The most recent session was last week and management’s offer wasn’t close to meeting union demands, Singh told CNN Business. He would not disclose what percentage increase the union is seeking, but said that unlike some recent strikes and labor talks that focused on working conditions, this one is first and foremost about wages.

“This really is at the end of the day about economics,” he said. “Jobs at the airport used to be great jobs. They have a benefit package you can’t find a lot of other places. But members are having to take second jobs at the airport to supplement their income.”

The majority of its workers make $17.05 per hour, according to the union, just pennies above San Francisco’s $16.99 per hour minimum wage. There is now a higher minimum wage of $19.15 an hour for jobs on city-owned properties, which includes the airport, but these union workers are still under the 2018 contract.

The current wage doesn’t provide a livable wage in the San Francisco Bay Area, the union says, and wages were well above the $15 an hour minimum level in effect when the last contract was negotiated in 2018. The contract includes fully-paid health care and a traditional pension plan.

“I’m on strike because I want to quit my second job and have more time with my family,” said Kristine Mauricio, a barista at both Peet’s Coffee and Black Point Cafe. “I have to work two jobs to support my son, and it means I barely get to be with him because I am always at work. My pay for a whole hour of work is less than the price of just one meal. That is 100% unfair.”

Strikes have been on the rise across the US and in multiple industries so far this year. A database kept by Cornell University’s School of Industrial and Labor Relations shows 283 strikes this year, up 82% from 155 in the same period of 2021.

Workers have been emboldened by a strong labor market, with about twice as many job openings as there are unemployed job seekers, which makes it difficult for employers to hire replacement workers to take the place of strikers.

Only 1.2% of workers at restaurants and bars are members of a union according to Labor Department data for 2021, compared to 6.1% of workers at businesses overall.

Wages in the sector are typically low, with Labor Department data showing that median weekly wages nationwide are $607 for nonunion workers, and $725 for the small percentage of workers who represented by a union.

The food service sector has a particularly high turnover rate among unhappy employees, with twice the rate of workers quitting as at businesses overall, which has helped to feed unionization efforts at other companies. A union effort has won votes at more than 200 Starbucks stores nationwide, and last month workers at a Chipotle in Lansing, Michigan voted to join the Teamsters.