Not sure what you mean. Manchin is against new regulations that make it harder to obtain natural gas pipeline permits.
Permitting processes are already long, laborious, red tape strangled deals and adding consideration of "greenhouse gasses" and "vulnerable communities" (whatever that is) to the list of hoops to jump through is just making it even harder to put a new line in.
States already have regulations governing land use in the vicinity of pipelines or existing residential and commercial areas, so I'm really not sure what they mean by "vulnerable" communities unless it is some sort of racist catch-all for whatever the regulators want to throw at pipeline companies at the time.