In the mid-1990s, California became the first state to ban smoking tobacco in bars, clubs and restaurants. Now, if a bill introduced last month by one Golden State Democrat becomes law, California would likely become the first state to prohibit millions of its citizens from smoking in their own homes.

The bill, authored by Assemblyman Marc Levine (D-San Rafael), would prohibit smoking inside all multiunit residences, such as condos or apartments, where housing units share walls, floor, ceilings or ventilation systems.

Free-standing homes, which make up about two-thirds of all residencies in the state, would be exempted from the ban.

"Californians should be able to breathe clean air in their own homes," Levine said in a statement. "In apartments or condominiums, whenever a neighbor lights up, everyone in the building smokes with them. This is especially troublesome for children who have no choice but to breathe the secondhand smoke of their neighbors."

The bill has raised a few eyebrows among housing advocates. The Sacramento Bee reports:

Brian Augusta, of the Western Center on Law and Poverty, said that targeting multifamily units disproportionately affects low-income people who can't afford standalone homes. "If smoking is an addiction, and it clearly is, are we telling people that they have to quit smoking--without support--or leave their homes?" he said.

San Rafael, one of the largest towns in Levine's assembly district, instituted a similar ban on smoking in multiunit housing last year--becoming the ninth municipality in the state to do so.

"The San Rafael ban is a very significant event because it will spread," Stanford University history of science professor Robert Proctor explained to Reuters "We're on the downslope of a big curve. Smoking peaked in 1981 with 630 billion cigarettes sold in the United States. Now it's down to 350 billion. And that number will keep on going down until smoking is a distant memory."

California's smoking rate has dropped precipitously in the past three decades. According to the California Department of Public Health, just over a quarter of Californians smoked cigarettes in 1984. In 2010, only 11.9 percent did, leaving California second only to Utah in having the lowest smoking rate in the country.