The Fair Chance in Housing Act took effect Jan. 1, and was hailed by supporters as a landmark measure to help formerly incarcerated people find safe places to live. Under the law, a landlord can’t prohibit someone with a criminal background from applying for housing, or ask about an applicant’s prior convictions before conditionally offering the applicant the unit.

But even after a landlord runs a criminal background check on a potential tenant or asks about the applicant’s criminal past, the landlord can only deny them housing if the criminal conviction occurred within a certain timeframe or the person was convicted of murder or kidnapping. A landlord must also put any denial in writing, along with an explanation on how the would-be tenant poses a safety risk to others. The tenant then has a chance to appeal the decision.

More serious offenses like carjacking can be used as a basis for denial if they happened within a six-year period. Less serious offenses such as assaults can be considered if they occurred within the last year, according to the law.

New Jersey Attorney General Matt Platkin said the measure, which is the first of its kind in the country, “reflects our state’s deep and unwavering commitment to ensuring that every New Jersey resident has a fair chance to find safe, affordable housing.”

The enforcement action comes after the attorney general’s office sent seven cease-and-desist letters in March to landlords it said had posted apartment ads explicitly saying people with criminal convictions could not apply.

The 30 newly cited landlords could face civil penalties of $1,000 for a first offense and up to $10,000 for repeat violations. Those who agree to amend their policies and undergo training can pay a fee to avoid the most costly penalties. The attorney general’s office said those fees vary in each case.

Alex Staropoli, director of advocacy and communications for the Fair Share Housing Center, applauded the enforcement steps.

“Laws without enforcement are meaningless. The Fair Chance in Housing Act purposely included a strong enforcement mechanism because we know that enforcement is critical to addressing housing discrimination in our state,” she said in an emailed statement.

She said the center’s hope “is that with continued education and outreach this legislation can begin to transform access to housing in New Jersey.”

Tenants can also file complaints with the attorney general’s office online or by calling 833-NJDCR4U. The office said seven complaints have been filed to date.

Officials declined to name the cited landlords but said they spanned 14 of the state’s 21 counties, including the following municipalities: Marlton, Woodbury, Princeton, Glassboro, Florence, Metuchen, Newark, Trenton, Midland Park, Cinnaminson, Cherry Hill, Passaic, Elizabeth, Berlin, Roebling, Hamilton, Burlington, Jersey City, Toms River, Bayville, Carneys Point, Little Ferry, Vineland, Lawrenceville, Asbury Park, and Bridgeton.