Hundreds of Longshoremen Thursday morning stormed the port in Longview, Wash. in a labor dispute-overpowering security guards as they dumped grain and damaged rail cars, the Associated Press reports.

Six guards were detained for a couple hours after approximately 500 Longshoremen broke into the facility, according to Longview Police Chief Jim Duscha. Union members then proceeded to dump grain and turn over a private security car before going back to their union hall to shoot off fireworks, Duscha said.

Union leaders said they did not call for this action. Rather, they said members acted on their own accord.

A court hearing was expected to take place later on Thursday in Tacoma, Wash. to determine if the actions violated a previous restraining order, according to the Associated Press. The Seattle Times reports that a restraining order was placed on the union after members had made death threats and were accused of assaulting EGT officials.

These events follow a protest on Wednesday evening, where union workers stood on the train tracks and clashed with police, leading to 19 arrests that evening, said the Tacoma News. On Thursday, many Longshore workers from around the state failed to show up in order to stand up for their fellow workers.

The dispute revolves around a new grain terminal operated by EGT. Member of The International Longshore and Warehouse Union believe they have the right to work at the facility, but EGT has hired a contractor that will staff the terminal with other union laborers, the Seattle Times reported. EGT wanted to hire another union, but the Port of Longview had a contract with ILWU.

Labor activists claim that after receiving tax breaks for the terminal and promising to create good-paying jobs, EGT initially tried to staff the terminal with nonunion workers, according to the Tacoma News.