Supporters of a bill calling for the state pension fund to gradually divest from fossil fuel companies see a 2010 law requiring divestment from companies holding financial interests in Iran as a template for success.

Sen. Benjamin Downing (D-Pittsfield) plans to press members of the Public Service Committee next Tuesday to approve his bill (S 1225), which calls for no new investments in fossil fuels and divestment over five years of holdings in companies that own fossil fuel reserves, as long as the aggregate value of the fund does not drop by more than 0.5 percent as a direct result of divestment.

According to Downingâs office, the pension fund has close to $1.4 billion invested in fossil fuels, including investments in Exxon Mobil, Chevron, Total S.A. and BP., investments that the senator believes conflict with governmentâs push to invest in renewable energy.

Downing, who co-chairs the Committee on Telecommunications, Utilities and Energy, plans to testify for his bill at an 11 a.m. Public Service Committee hearing at the State House on Tuesday morning, which will be preceded by a rally on the State House steps with bill supporters from the group 350MA.

According to 350MA, the Conservation Law Foundation, Environmental League of Massachusetts, Clean Water Action and Environment Massachusetts have signed a letter supporting the legislation. San Francisco and Seattle have committed to carbon divestment, according to Downingâs office.