** Shares of 3M MMM.N fell 3.1% premarket, after Australia sued the chemicals maker over PFAS "forever chemicals" in firefighting foam

** The Australian government seeks more than A$2 billion ($1.42 billion) in damages from MMM, alleging the firm assured that its foam used at 28 defense bases was safe to dispose of, biodegradable and non-toxic

** PFAS are a group of manufactured chemicals widely used in products resistant to heat, stains, grease and water. They do not naturally break down in the environment

** MMM has faced thousands of lawsuits over PFAS contamination, which analysts say is an overhang on its stock

** Analysts tracking the stock rate it "buy" on average, their median PT is $168 - data compiled by LSEG

** The stock has lost 3% this year, as of Wednesday's close, trailing the S&P 500's .SPX ~10% YTD rise

($1 = 1.4053 Australian dollars)