Delivery workers for United Parcel Service Inc. may go on strike and disrupt service if their demands are not met.

The current contract for UPS truck drivers and delivery employees started on Aug. 1, 2018. It is set to expire on July 31, 2023, but before it does, teamsters are asking for more benefits.

Represented by the International Brotherhood of Teamsters labor union, UPS employees are counting down till Aug. 1, 2023 to start their strike if the company doesn’t level with them.

Employees have been demanding for months that UPS provide better pay and more benefits, especially for part-time workers.

UPS said that its employees can make up to an average of $93,000 after working four years, according to a press release. However, job search services like ZipRecruiter report that the average salary of a UPS delivery worker tends to be around $38,000, which is much lower than what UPS said.

Through the COVID-19 pandemic, UPS raised hourly wages from $15.33 to $18, to keep workers from leaving. Although workers were told this change would be permanent at the time, UPS later told employees that it will be changing hourly wages back to $15.33.

The pay cut may make it difficult for workers who relied on the increased pay to get by, especially as the United States experiences high inflation.

“With inflation, $15.33 an hour is tough for workers and their families,” Alex Sanchez, who works part-time for UPS, told The Guardian. “I work two jobs in order to make ends meet. I’m a married father of three. The $3 cut really takes a toll on our family’s budget.”

Additionally, following an intense nationwide heat wave over the summer, the demand for air conditioning in delivery trucks grew. Drivers may deliver between 150 to 300 packages per day.

The heat-related death of 24-year-old UPS driver Esteban Chavez raised awareness of the lack of air conditioning in the company’s delivery  trucks. Matt Leichenger, who delivers packages in Brooklyn, tweeted about UPS denying his fan installation request for his truck.

To help get their voices heard, more UPS employees are joining the Teamsters union. Sean O’Brien, who serves as the union’s president, is aware of the upcoming “big fight” with UPS.

“We need everyone to join us as we take on the company in negotiations,” O’Brien told union members in Montana, according to a press release. “It’s time to mobilize and send a message that UPS Teamsters are united and ready to fight for a strong contract in 2023.”

The last time UPS workers held a strike was in 1997, and it lasted two weeks. If a new strike does happen, it is projected to become one of the biggest labor strikes in the nation’s history.

With strikes and unionizations happening in major companies like coffeehouse chain Starbucks Corp. and supermarket chain Trader Joe’s, UPS workers are also gaining more confidence in standing up to the company.

A strike may bring trouble to American customers. UPS delivers 21.5 million packages and transports 6% of the U.S. gross domestic product, both on a yearly basis.

Even if UPS’ competitors — such as Amazon.com Inc., FedEx Corp. and the U.S. Postal Service — were to take over the delivery of these packages, there still wouldn’t be enough workers to deliver them, according to an analysis by CNN.

With online shopping habits rising, reliance on package delivery services is also rising. Consumers would expect long delays or even lost packages since UPS would be running shortstaffed with non-union employees, thus creating frustration.

“UPS and the Teamsters have worked cooperatively for almost 100 years to meet the needs of UPS employees, customers and the communities where we live and work,” UPS said in a statement, as reported by CNN. “We believe we’ll continue to find common ground with the Teamsters and reach an agreement that’s good for everyone.”