The National Labor Relations Act contains protections for workers during labor disputes.
RIGHTS OF EMPLOYEES
Sec. 7. [§ 157.] Employees shall have the right to self-organization, to form, join, or assist labor organizations, to bargain collectively through representatives of their own choosing, and to engage in other concerted activities for the purpose of collective bargaining or other mutual aid or protection, and shall also have the right to refrain from any or all such activities except to the extent that such right may be affected by an agreement requiring membership in a labor organization as a condition of employment as authorized in section 8(a)(3) [section 158(a)(3) of this title].
You can read more at: http://www.nlrb.gov/about_us/overview/national_labor_relations_act.aspx
Also, the act includes information on concerted actions.
What are protected concerted activities?
The National Labor Relations Act (NLRA) protects employees’ rights to engage in protected concerted activities with or without a union, which are usually group activities (2 or more employees acting together) attempting to improve working conditions, such as wages and benefits. Some examples of such activities include:
a) 2 or more employees addressing their employer about improving their working conditions and pay;
b) 1 employee speaking to his/her employer on behalf of him/herself and one or more co-workers about improving workplace conditions;
c) 2 or more employees discussing pay or other work-related issues with each other.
The NLRA also protects any individual employee’s right to engage in union support, membership, and activities.
The NLRA protects an individual employee’s right not to engage in union activities or in other protected, concerted activities.
More information can be found at: http://www.nlrb.gov/Workplace_Rights/