BERKELEY -- The city's apartment and condominium complex dwellers will soon be free from neighbors' cigarette smoke wafting through air vents or curling up from balconies. The City Council this week unanimously approved a ban on smoking in multiunit buildings. The law will go into effect May 1, 2014.

According to United States census figures, 53 percent of the city's housing units are in multi-unit structures buildings.

"I am a cancer patient who lives next door to two chain smokers and on the other side of them are some really tiny children," Berkeley resident Carol Denney told the council at its Dec. 3 meeting in urging passage of the ordinance.

The U.S. Environmental Protection Agency classifies secondhand smoke as a Class A carcinogen, the class of the most dangerous carcinogens. Exposure to secondhand smoke causes some 3,000 lung cancer deaths every year in nonsmokers, and can cause asthma and sudden infant death in children, according to the EPA.

Berkeley is not the first city in California to write laws banning smoking in multiunit housing, Serena Chen of the American Lung Association noted, "but you are the first city to enforce it right."

Enforcement will be a complaint-driven multi-step process. Landlords or homeowners associations will be required to advise tenants or condominium owners of the law by March 1, 2014.

From there it will be up to the neighbors effected by secondhand smoke to make a formal complaint to the city's health department. When a complaint is filed, the city will issue a warning notice to the alleged violator -- the notice will include an explanation of the new law and information on smoking cessation classes the city offers.

If two residents in two separate units of the multi-unit residence file complaints within six months of the original notice, the city can issue either an administrative citation or an infraction.

While the council was unanimous in its support for the ordinance, Councilman Jesse Arreguin expressed concern about violations being charged as infractions.

Alleged violators can contest citations before a city hearing officer, but those given infractions may be required to go through a more formal judicial process.

Brendan Darrow, attorney with the East Bay Community Law Center, told the council he feared that "By calling this an infraction, there can be unintended collateral consequences."

He said, for example, an infraction might show up on a background check for an individual. Councilman Max Anderson said he was concerned with the potential consequences on a parolee charged with an infraction, rather than an administrative citation, for smoking.

But Mayor Tom Bates said the council should address the rights of nonsmokers.

"What about the rights of the people who live next door to the person (who smokes)?" he asked.

City Attorney Zach Cowan advised the council against removing the possibility of charging violators with infractions, basing his opinion on requirements found in the City Charter.

Responding to concerns, however, the council accepted a policy recommendation offered by Arreguin that states: "It's the sense of the council that staff should consider employing an administrative citation first" before an infraction.

Previous iterations of the ordinance suggested the smoking ban should apply to single-family homes and to marijuana smoke.

The approved ordinance, however, applies strictly to multiunit dwellings and to tobacco -- not cannabis -- smoke.