Puerto Rico Constitution
Article II - Bill of Rights
Section 18.

Section 18. In order to assure their right to organize and to bargain collectively, persons employed by private businesses, enterprises and individual employers and by agencies, enterprises and individual employers and by agencies or instrumentalities of the government operating as private businesses or enterprises, in their direct relations with their own employers shall have the right to strike, to picket and to engage in other legal concerted activities.

Nothing herein contained shall impair the authority of the Legislative Assembly to enact laws to deal with grave emergencies that clearly imperil the public health or safety or essential public services.