The California Assembly in the US has approved a new bill, SB 185 (De León), allowing the state pension funds, California Public Employees’ Retirement System (CalPERS) and California State Teachers’ Retirement System (CalSTRS), to divest their investments in coal firms.

The bill was passed on a 43-27 vote and it will now be forwarded for governor’s approval.

California Senate president pro Tempore Kevin de León said: "Coal is losing value quickly and investing in coal is a losing proposition for our retirees; it’s a nuisance to public health; and it’s inconsistent with our values as a state on the forefront of efforts to address global climate change.

"California’s utilities are phasing out coal, and it’s time our pension funds did the same."

The SB 185 is expected to be the first measure of its kind across the country, if it is signed into law.

With around $292bn and $191bn worth assets, CalPERS and CalSTRS are claimed to be the largest public pension funds in the nation.

CalPers has invested in around 20 to 30 thermal coal mining firms valued at around $100m to $200m, while CalSTRS has holdings of $40m, reported Reuters.