Boeing announced it will take several weeks to fully resume the production of passenger aircraft as factory employees return from a nearly two-month strike.

A company representative indicated on Tuesday that the factories in Washington state and Oregon are experiencing delays due to the various steps necessary to restart operations.

Each returning employee will undergo a briefing regarding their responsibilities and safety protocols, and the company will ensure that all training certifications are up to date, according to the spokesperson.

Approximately 33,000 workers, represented by the International Association of Machinists and Aerospace Workers, initiated a strike on September 13 primarily concerning wages and pension benefits. Last week, they approved Boeing’s contract proposal and were instructed to report back to work by Tuesday.

The strike resulted in the suspension of production for the 737 Max, 777 passenger planes, and a cargo variant of the 767. However, Boeing maintained some production of the 787s, which are assembled by nonunion employees in South Carolina.

As a result of the strike, Boeing’s delivery cash flow was significantly impacted, with the company reporting delivery of just 14 planes in October, most of which had been completed before the labor dispute began. Additionally, Boeing secured orders for 63 aircraft, including 40 737 Max jets from leasing company Avia Solutions Group.