(Bloomberg) — The U.S. Department of Health and Human Services (HHS) will be giving some Americans a second chance to avoid the Patient Protection and Affordable Care Act (PPACA) individual mandate tax penalty.

Officials at the Centers for Medicare & Medicaid Services (CMS) said they will add an extra major medical special enrollment period (SEP) that will last from March 15 through Apri 30. 

The PPACA is set to impose a penalty of 1 percent of income on many Americans who failed to have what the government defines as adequate coverage throughout 2014. The penalty rate for consumers who lack coverage in 2015 is set to rise to 2 percent. Personal income tax filings for 2014 are due April 15, and many taxpayers are just learning about the penalties they owe for 2014.

Regular sign-ups for 2015 coverage ended Sunday.

The new SEP will be available to consumers in states with public exchanges operated by HHS who attest that they have paid a PPACA mandate penalty for 2014 and first learned of the penalty system when they filed their 2014 taxes.

Andy Slavitt, principal deputy administrator at CMS, announced the move on a conference call Friday.

“Our intention that this is for one year only, for people who have not been in the communication loop,” Slavitt said.

Slavitt also said the administration sent about 800,000 Americans wrong information, which can affect how much they owe in taxes. The U.S. is asking them to hold off on filing their 2014 returns until they can correct the error, though about 50,000 people have already done so and will need to re-file.

The wrong information was a “glitch,” Slavitt said, that resulted in miscalculations of subsidies some taxpayers receive to help pay for their health coverage.

States that operate their own PPACA exchanges can decide whether they’ll hold their own special enrollment periods.

The Treasury Department has estimated as many as 6 million people may owe the penalty for not carrying insurance in 2014. About 11.4 million people have signed up for insurance this year under PPACA. Slavitt said he doesn’t know how many might be eligible for the extra enrollment period.

The administration will also add a feature to HealthCare.gov that helps consumers determine whether they’re eligible for a waiver from having insurance so they can avoid the tax penalty.

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