After months of negotiations, strike threats and walkout talks, UPS and Teamsters, the union representing 340,000 UPS workers, have reached a tentative agreement on a new five-year labor contract.

The agreement avoided what would have been the largest single employer strike in U.S. history and came after the groups resumed talks earlier this week.

"The overwhelmingly lucrative contract raises wages for all workers, creates more full-time jobs andincludes dozens of workplace protections and improvements," a news release from Teamsters stated.

The Teamsters' national negotiating committee unanimously supported the tentative agreement for the full new contract.

"We demanded the best contract in the history of UPS, and we got it,” said Sean O'Brien, International Brotherhood of Teamsters general president. "We’ve changed the game, battling it out day and night to make sure our members won an agreement that pays strong wages, rewards their labor, and doesn’t require a single concession. This contract sets a new standard in the labor movement and raises the bar for all workers.”

The five-year agreement covers U.S. Teamsters-represented employees in small-package roles and is subject to voting and ratification by union members, Jim Mayer, a UPS spokesperson, told the Louisville Courier Journal, part of the USA TODAY Network. Ratifying the contract could take about three weeks, according to previous statements from O'Brien, and Secretary-Treasurer Fred Zuckerman.

"Together we reached a win-win-win agreement on the issues that are important to Teamsters leadership, our employees, and to UPS and our customers," said Carol Tomé, UPS chief executive officer. “This agreement continues to reward UPS’s full- and part-time employees with industry-leading pay and benefits while retaining the flexibility we need to stay competitive, serve our customers and keep our business strong."

The UPS-Teamsters deal:Here's what workers are getting

Here's what we know about UPS and Teamsters reaching a contract.

How did we get here?

The bargaining process started last August with the introduction of a contract campaign.

In March, regional unions began the bargaining process with UPS over supplemental contracts for their employees. By mid-May, tentative agreements had been reached on all supplements except two: Louisville and Northern California. Those regions finally agreed to tentative terms in late June.

Negotiations over the national contract began in April. Teamsters won a crucial bargaining point for members in mid-June when UPS committed to equip delivery vehicles with air conditioning and take other precautions for heat safety. But with other demands unmet, union members passed a strike authorization vote with 97% approval on June 16, giving them the ability to call a strike if they deemed it necessary.

A strike appeared imminent on June 28, when Teamsters walked away from the bargaining table and members began holding practice pickets nationwide, including in Louisville. But after UPS presented a "revised counterproposal with significant movement on wages and other economic language," the two parties were able to come to a tentative agreement on several unresolved issues.

By June 30, it appeared Teamsters and UPS were poised to reach a contract "no later than July 5," but within a day's time that promise faded with both sides walking away from the bargaining table and blaming the other for negotiations coming to a standstill.

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In the days after walking away from the table earlier this month, the two sides began preparing for a strike, with UPS beginning "continuity training" for management employees who would not be covered under a possible Teamsters strike. On the other side, Teamsters union barns across the country have been hosting practice pickets and nationwide rallies featuring O'Brien and Zuckerman.

In Louisville, Zuckerman, who for 40 years was a member of Teamsters Local 89 — the union representing around 10,000 Louisville-area UPS workers — led two rallies in the metro. The morning rallies took place at Louisville Centennial Hub and UPS Worldport, the largest sorting and logistics facility in America.

On July 14, O'Brien shifted his tone and "said he's ready to keep talking with the company, even though his bargaining committee rejected its latest contract offer," Reuters originally reported. O'Brien also asked the White House to not intervene in negotiations.

On July 16, O'Brien said, "If we don't come to a tentative agreement by July 31 at 12:01 a.m., we will be striking, we will not work without a contract."

Has UPS met any of the Teamsters' demands?

To date, the Teamsters and UPS have reached a tentative agreement on more than 55 non-economic issues, with the union winning everything it wanted for its members, O'Brien said previously.

Some tentative agreements reached prior to the July 5 walkout included: ending forced overtime on drivers' days off, establishing Martin Luther King Jr. Day as a paid holiday and increasing wages through reclassification for flexible drivers who do not work traditional Monday-Friday shifts.

What happens now?

Teamsters need to disseminate the full tentative agreement contract to all members and give them a chance to read the contract, ask questions and vote.

Teamsters leaders anticipate the ratification process to take three weeks. During that time, Teamsters will continue to work even though the current governing contract will have expired.

After the contract is ratified by members, it will become the governing body for labor relations between the company and the union.

Contact reporter Olivia Evans at [email protected] or on Twitter at @oliviamevans_.