US EPA suggested to amend the national marine diesel engine program to provide relief provisions to address concerns regarding the finding and installing certified Tier 4 marine diesel engines in certain high-speed commercial vessels.
The proposed relief is in the form of additional lead time for qualifying engines and vessels. The proposal also contains waiver provisions to enable the continued installation of Tier 3 engines for certain ships if suitable Tier 4 engines continue to be...
https://safety4sea.com/us-epa-considers-amendments-for-marine-diesel-engine-emission-standards/