Responding to an investigation by this newspaper, a state lawmaker introduced legislation Tuesday to ban future part-time elected officials from receiving taxpayer-funded health insurance after they leave office.

Assemblyman Kevin Mullin, D-South San Francisco, said he hoped to unburden local governments from costs that can stretch on for decades after elected leaders leave office.

"It doesn't make sense for part-time elected officials to earn lifetime health benefits," he said. "The public thinks that benefits expire when the term expires, and that's obviously not the case."

This newspaper reported last month that more than 200 former Bay Area politicians receive medical insurance from the governments where they once held office. Some, such as three former trustees of the West Contra Costa Unified School District in Richmond, were elected in the 1960s and have been out of office for more than 30 years.

At the Santa Clara Valley Water District, former director Patrick Ferraro received health coverage for himself and two dependents in 2012 that cost nearly $50,000. He's been out of office since 1995.

In 19 cases, the dependents of dead former officials received benefits in 2012, government data showed.

Mullin's bill would ban anyone sworn in after Jan. 1, 2015, from receiving medical coverage after they leave office.

But his proposal won't take away the benefit from anyone receiving it now, he said in a telephone interview.

Lawyers for the legislature were quick to nix that idea, defining the perk as a vested right for hundreds of former city council members, school trustees and water district directors.

"We're trying to do this without causing a ton of lawsuits," Mullin said. "There may be some legacy costs" for those currently receiving coverage, "but it will eventually end."

A 1995 law already bans the benefit for anyone elected after 1996 to a special district -- such as a water or park agency.

Mullin said he was still exploring whether the legislature could force former officials who receive the benefit through the state Public Employees Retirement System, CalPERS, to pay a larger share of the benefits of the cost.

In some cases, governments are contributing less than $1,500 a year for that health coverage with the former officials paying the bulk of the cost. But others, such as Palo Alto, are paying 100 percent of the expense. That city spent more than $115,000 in 2012 to cover 13 former politicians.

A CalPERS spokesman, Brad Pacheco, said in an email on Tuesday that local governments could require people to pay more of the cost. The legislature could also force such a change, he said.

Ferraro, whose benefits are not through CalPERS, said Tuesday that he can't support Mullin's proposed statewide ban.

"I don't think the bill is a good idea," he said. Providing the benefit "has to be a local philosophy. All politics is local."

Contact Thomas Peele at tpeele@bayareanewsgroup.com and follow him twitter.com/thomas_peele