The U.S. Navy says its use of sonar and explosives could potentially hurt more dolphins and whales in Hawaii and California waters than previously thought.
The new research and more thorough analysis are part of an environmental impact statement covering Navy training and testing planned for 2014 through 2018.
The Navy estimates its use of explosives and sonar may unintentionally cause more than 1,600 instances of hearing loss or other injury to marine mammals in one year.
Its use of explosives may inadvertently cause more than 200 marine mammal deaths a year.
The old analysis -- covering 2009 through 2013 -- estimated the service might unintentionally injure or kill about 100 marine mammals.
The Navy says the actual numbers would be lower because it takes steps to prevent harm to the animals.