Low-income Americans who live in states that have decided not to expand Medicaid eligibility will not face penalties if they fail to buy insurance next year.

That’s according to a final rule on exemptions to the health law’s individual mandate – the law’s controversial requirement  that most Americans have health coverage or pay a penalty in 2014. That rule was published Wednesday.

The health law calls for an expansion of Medicaid, the federal-state insurance program for low-income Americans, by making it available to people up to 138 percent of the federal poverty level, which for individuals is $15,856 in 2013, and providing new federal funding to cover the costs for the first three years, and no less than 90 percent after that. But the Supreme Court ruled last year that states could not be forced to join in that program. About half the states so far have opted against the expansion, a concern for supporters of the law because it could leave millions of people without access to affordable coverage.

The law provides subsidies to help low-income people, but they are available only to those who earn between 100 and 400 percent of the poverty level. Individuals and families earning less than 100 percent who live in states not expanding Medicaid have few, if any, options for affordable insurance.

The final rule is similar to draft proposals from the U.S. Department of Health and Human Services and Treasury in January.

Those who do not have health coverage, and who do not meet the criteria for exemptions, must pay the penalty at the end of the tax year.  The penalty for the first year is $95 per adult and $47.50 per child, or 1 percent of family income, whichever is greater, and it increases over time.

This story has been corrected to reflect that 138 percent of the federal poverty level for single adults is $15,856.