Smoking will be prohibited in public housing developments nationwide under a final rule announced Wednesday by the Obama administration.

The Centers for Disease Control and Prevention says the smoke-free policy will save housing agencies $153million every year in repairs, preventable fires and health care costs.

That amount includes $16million in costs associated with smoking-related fires.

The Department of Housing and Urban Development has been encouraging local public agencies to enact smoking bans, and some 228,000 public housing units were already smoke-free.

The new rule will expand the impact to more than 940,000 units.

Smoking will be prohibited in public housing developments nationwide under a final rule announced Wednesday by the Obama administration (file)

In announcing the ban, administration officials emphasized the dangers of secondhand smoke to children, saying it can increase the risk of asthma, ear infections, even sudden infant death syndrome.

'Every child deserves to grow up in a safe, healthy home free from harmful secondhand cigarette smoke,' HUD Secretary Julián Castro said.

The ban is expected to affect two million Americans, including 760,000 children and more than 300,000 senior citizens who live in more than 940,000 public housing units, HUD said.

More than 600 of the nation's 3,100 public housing agencies already prohibit indoor smoking.

'Every child deserves to grow up in a safe, healthy home free from harmful secondhand cigarette smoke,' HUD Secretary Julián Castro (pictured in July) said

The new rule extends the ban to smoking cigarettes, cigars and pipes within 25 feet of all federally owned apartments, public areas and administrative offices.

Electronic cigarettes are exempted.

The new rule gives public housing agencies 18 months to implement the ban.

'Protecting people from secondhand smoke saves lives and saves money,' said CDC Director Tom Frieden.

'No level of secondhand smoke exposure is safe, and the home is the primary source of secondhand smoke for children.'

The Campaign for Tobacco-Free Kids applauded HUD's actions, saying 'this bold step' would reduce smoking among groups that suffer the most from tobacco-related death and disease.

The organization said HUD also should have gone further and applied the ban to electronic cigarettes, though local housing authorities are permitted to do so.

Two in five children living in federally subsidized housing are exposed to second-hand smoke, according to a 2015 CDC study (file)

HUD Secretary Julián Castro said he was optimistic the Trump administration would not 'roll back' the rule.

'I'm convinced that no matter the political persuasion, the public health benefit is so tremendous and the resident support for going smoke free is so tremendous that this rule will stick,' he said during a conference call.