A looming dock worker strike could slow down the Port of Mobile’s record-breaking year.

Next week, If an agreement isn’t reached by midnight on October 20, the International Longshoremen’s Association (ILA) Local 1410 will strike CSA Equipment Company, a stevedoring (unloading) provider at the port, after union membership voted not to accept CSA’s latest contract offer. Dock workers represented by Local 1410—about 800 people–will refuse to work with CSA, with very few exceptions.

Though CSA is one of several stevedoring companies that are licensed to operate at the port, the strike is sure to have an impact on port operations, which continue to grow as the volume of containers that move through the port increase. In fact, the Alabama Port Authority announced yesterday that the port handled the most containers per month in September since 2008, when APM Terminals began operations at the port.

There are three major issues that are causing the holdup in the labor agreement: line handling, or tying up vessels, retroactive benefits for the last few years, and the number of workers per unit, according to Mark Bass, president of Local 1410.

Union workers want to have sole control over line handling. As it stands right now, union workers cannot tie up vessels that are handled by non-unionized stevedoring companies, but non-unionized workers can tie up vessels handled by CSA. Local 1410 wants to line handle for all the vessels that CSA is contracted to unload, which is more man-hours for its workers, Bass says.