Nine anti-genetically modified food activists were arrested this week during their protest against Monsanto, who is against Proposition 37, which would require the labeling of foods containing ingredients derived from genetically modified plants.

The people arrested are members of Occupy Monsanto, a group opposed the use of genetically modified crops and chemical crop protection products. The activists protested in front of Monsanto’s Seminis Vegetable Seeds Inc. plant in Oxnard, Calif. The group consisted of five men and four women. They were arrested after police say they blocked three shipping and receiving gates at the plant.

Police were called after trucks from the plant could not get through the gate and the company could not conduct its business. The protestors locked themselves to vehicles and shackled themselves together.

The protest was against Monsanto, who, along with other companies, are against Prop 37, but a spokesperson for Occupy Monsanto said the protest wasn’t specifically related to Prop 37. Occupy Monsanto activist Rea Abileah said the group held the protest to begin its upcoming global week of actions against Monsanto starting Monday, with similar events to take place at other company facilities in the U.S. and overseas, according to the Ventura County Star.