The number of young Americans without a job has exploded to 53.4 percent — a post-World War II high, according to the Labor Dept. — meaning millions of Americans are staring at the likelihood that their lifetime earning potential will be diminished and, combined with the predicted slow economic recovery, their transition into productive members of society could be put on hold for an extended period of time.

The number represents the flip-side to the Labor Dept.’s report that the employment rate of 16-to-24 year olds has eroded to 46.6 percent — the lowest ratio of working young Americans in that age group, including all but those in the military, since WWII.

And worse, without a clear economic recovery plan aimed at creating entry-level jobs, the odds of many of these young adults — aged 16 to 24, excluding students — getting a job and moving out of their parents’ houses are long. Young workers have been among the hardest hit during the current recession — in which a total of 6.9 million jobs have been lost.

“It’s an extremely dire situation in the short run,” said Heidi Shierholz, an economist with the Washington-based Economic Policy Institute. “This group won’t do as well as their parents unless the jobs situation changes.”

Al Angrisani, the former assistant Labor Department secretary under President Reagan, doesn’t see a turnaround in the jobs picture for entry-level workers and places the blame squarely on the Obama administration and the construction of its stimulus bill.

“There is no assistance provided for the development of job growth through small businesses, which create 70 percent of the jobs in the country,” Angrisani said in an interview last week. “All those [unemployed young people] should be getting hired by small businesses.”

There are six million small businesses in the country, those that employ less than 100 people, and a jobs stimulus bill should include tax credits to give incentives to those businesses to hire people, the former Labor official said.

“If each of the businesses hired just one person, we would go a long way in growing ourselves back to where we were before the recession,” Angrisani noted.

During previous recessions, in the early ’80s, early ’90s and after Sept. 11, 2001, unemployment among 16-to-24 year olds never went above 50 percent. Except after 9/11, jobs growth followed within two years.

A much slower recovery is forecast today. Shierholz believes it could take four or five years to ramp up jobs again.

A study from the National Longitudinal Survey of Youth, a government database, said the damage to a new career by a recession can last 15 years. And if young Americans are not working and becoming productive members of society, they are less likely to make major purchases — from cars to homes — thus putting the US economy further behind the eight ball.

Angrisani said he believes that Obama’s economic team, led by Larry Summers, has a blind spot for small business because no senior member of the team — dominated by academics and veterans of big business — has ever started and grown a business.

“The Reagan administration had people who knew of small business,” he said.

“They should carve out $100 billion right now and create something like $5,000 to $6,000 job credits that would drive the hiring of young, idled workers by small business.”

Angrisani said the stimulus money going to extending unemployment benefits is like a narcotic that is keeping the unemployed content — but doing little to get them jobs.

Labor Dept. statistics also show that the number of chronically unemployed — those without a job for 27 weeks or more — has also hit a post-WWII high.