The Navy's use of sonar and explosives could deal damage to some 1,600 marine mammals near California and Hawaii every year—a figure far higher than once believed. The whales and dolphins are at risk of hearing loss and other injuries, the AP reports. What's more, the explosives could accidentally kill up to 200 animals. An earlier study assessing the risk between 2009 and 2013 predicted that just 100 creatures could be hurt or killed. The new research is part of an environmental impact statement that considers the Navy's plans between 2014 and 2019.