HUMBOLDT COUNTY, California (CNN)-- Sources from the Humboldt County Sheriff's Office confirmed to CNN that pepper spray was used in an incident with anti-logging protestors Wednesday morning.

In a written statement, the sheriff's department says pepper spray was directly applied to two protestors when they actively resisted arrest. The two were part of a group of four who had locked themselves to logging equipment.

The incident took place on Highway 36 near Carlotta on the same road Earth First activist David Chain was killed by a falling log on September 18.

In a press release issued Thursday, Earth First says its blockade next to Grizzly State Park is to protect the area until an independent investigation into his death can be conducted. Earth First protesters said they will maintain the blockade until the investigation is done and Pacific Lumber/Maxxam discontinues logging and cutting old growth.