June 27 (Reuters) - Federal regulators on Thursday approved a Louisiana liquefied natural gas project that has been a lightning rod for environmental activists and a litmus test for the Biden administration's energy policies.

The Federal Energy Regulatory Commission voted to allow construction and operation of the Calcasieu Pass 2 LNG plant and a related, 85-mile-long (137 km) pipeline. (Reporting by Curtis Williams in Houston and Tim McLaughlin in Boston)