29 U.S.C. § 143 : US Code - Section 143: Saving provisions

      Nothing in this chapter shall be construed to require an
    individual employee to render labor or service without his consent,
    nor shall anything in this chapter be construed to make the
    quitting of his labor by an individual employee an illegal act; nor
    shall any court issue any process to compel the performance by an
    individual employee of such labor or service, without his consent;
    nor shall the quitting of labor by an employee or employees in good
    faith because of abnormally dangerous conditions for work at the
    place of employment of such employee or employees be deemed a
    strike under this chapter.