The National Labor Relations Board ruled Thursday Boeing violated federal law by photographing and videotaping members of the engineers union during meetings at Boeing plants in Washington and Oregon in 2012.

The Society of Professional Engineering Employees in Aerospace filed the complaint against the Chicago-based aerospace company in October 2013 after it said Boeing used surveillance and confiscated cameras from employees during separate events in the Pacific Northwest.

The 25,000-member union believes surveillance intimidates workers not to participate.

The ruling requires the Chicago-based aerospace company to post notices in the workplace saying, among other things, it will not photograph or videotape employees during marches and rallies at the work place or near Boeing property. Employees can still use cameras in non-restricted areas, according to the ruling.

Boeing makes parts for and assembles the 787 Dreamliner in North Charleston and Everett, Wash. The North Charleston plant is not unionized.