The White House has eased vaccine mandates for federal contractors, giving them broad flexibility in how they choose to enforce the rules for millions of workers after businesses pushed back over concerns of possible supply chain disruptions.

“A covered contractor should determine the appropriate means of enforcement with respect to its employee at a covered contractor workplace who refuses to be vaccinated and has not been provided, or does not have a pending request for, an accommodation,” said the new guidelines, which affect millions of workers.

“This may include the covered contractor using its usual processes for enforcement of workplace policies, such as those addressed in the contractor’s employee handbook or collective bargaining agreements.”

Contractors can offer extensions to the deadline based upon medical considerations and should “take note that an individual’s medical need should be considered on a case-by-case basis, including any medical evaluation that addresses the individual’s particular circumstance.”

President Joe Biden in September issued an executive order mandating vaccinations for all federal contractor employees by Dec. 8.

At least 20 states filed lawsuits asking a federal judge to block the requirement, arguing it violates federal procurement law and is an overreach of federal power.

“If the federal government attempts to unconstitutionally exert its will and force federal contractors to mandate vaccinations, the workforce and businesses could be decimated, further exacerbating the supply chain and workforce crises,” Missouri Attorney General Eric Schmitt said in a statement.

Texas Attorney General Ken Paxton separately sued the Biden administration Friday, saying it has “committed repeated and abusive federal overreach to force upon Americans something they do not want.”

Federal contractors include companies like IBM, Boeing, Southwest Airlines, and American Airlines.