The missed deadlines have pushed the government’s decision on whether information technology security is up to snuff to exactly one day before that crucial date, the Department of Health and Human Services’ inspector general said in a report.

As a result, experts say, the exchanges might open with security flaws or, possibly but less likely, be delayed.

“They’ve removed their margin for error,” said Deven McGraw, director of the health privacy project at the non-profit Center for Democracy & Technology. “There is huge pressure to get (the exchanges) up and running on time, but if there is a security incident they are done. It would be a complete disaster from a PR viewpoint.”

The most likely serious security breach would be identity theft, in which a hacker steals the social security numbers and other information people provide when signing up for insurance.