In the FAA Reauthorization Act of 2018, Section 317 prohibits helicopters manufactured after April 5, 2020, from flying in U.S. airspace unless certified with a crash resistant fuel system.  The online toolkit (link below) explains which helicopters will require a crash resistant fuel system according to their certification and manufacturing dates and also offers extensive background information on the topic.

https://www.faa.gov/aircraft/air_cert/design_approvals/rotorcraft/media/helicopter_occupant_safety_toolkit.pdf