The union representing Google workers has filed two unfair labor practices complaints with the National Labor Relations Board, alleging Google and the contracting companies retaliated against workers for organizing.

The Alphabet Workers Union-Communications Workers of America announced the complaints on Thursday.

In one complaint, the union said several contract workers working through Modis faced intimidation after attempting to organize. In one example, the union said a worker suggested a walkout to protest a new time clock policy. The suggestion was made in a private worker chat, and the union said workers currently use online software to clock in and a physical time clock would provide needless disruption to the workday. However, the worker in this example was later pulled aside by a manager and told that “Google and Modis management” were unhappy.

Also, at the same worksite, the union claims two other workers were effectively fired when their contract was not renewed because of their affiliation with the union. Both Modis and Google have been charged as joint employers in that complaint.

Modis said it has been made aware of the situation and is taking these allegations seriously. It is assessing the situation and cannot comment further.

In the second complaint, the union said the security clearances of two security officers with Allied Universal were revoked following their involvement in a union campaign. One security guard was at a facility in Lenoir, North Carolina, and the other was at a site in Moncks Corner, South Carolina.