https://www.nlrb.gov/about-nlrb/rights-we-protect/the-law/employees/concerted-activity-0#:~:text=Your%20employer%20cannot%20discharge%2C%20discipline%2C,activity.%20However%2C%20you%20can%20lose
From the NLRB about "Concerted Activity"
"You have the right to act with coworkers to address work-related issues in many ways. Examples include: talking with one or more co-workers about your wages and benefits or other working conditions, circulating a petition asking for better hours, participating in a concerted refusal to work in unsafe conditions, and joining with coworkers to talk directly to your employer, to a government agency, or to the media about problems in your workplace."