Though the Obama administration in March put a halt on drilling for oil and gas in Atlantic, the dolphins and whales inhabiting the waters are still at risk, says one ocean conservation group, as proposed seismic airgun blasting to look for reserves of the fossil fuels would leave the marine mammals “profoundly impacted.”

The scale of the threat they face was laid bare on Wednesday with a pair of new maps released by by Oceana. Based on extensive research from Duke University’s Marine Geospatial Ecology Lab, the maps—one for bottlenose dolphins and the other for endangered humpback, fin, and sperm whales—show the overlapping areas of the proposed blasting in the area stretching from Delaware to Florida and the density of the whales and dolphins in those waters over a 12-month period.

“These animated maps clearly show that marine life, including dolphins and whales, would be profoundly impacted by the proposed seismic blasting,” stated Dr. Ingrid Biedron, marine scientist at Oceana.

With this kind of exploration, Oceana states, blasts are “repeated every ten seconds, 24 hours a day, for days to weeks at a time.” The impacts of such blasting, as the group has explained, can include temporary or permanent hearing loss, and, because whales and dolphins “rely on their hearing to find food, communicate, and reproduce, being able to hear is a life or death matter.” The Center for Biological Diversity has also described the blasting as “actually a blunt-force weapon,” as it emits “the loudest human sounds in the ocean, short of those made by explosives.”

By the government’s own estimates, Oceana adds, up to 138,000 whales and dolphins could be harmed, and millions more disturbed, by the blasting.