They were a true blast from the past.

World War II-era munitions, such as anti-submarine weapons and smoke devices, were discovered in underwater dump sites off the Los Angeles coast, marine researchers announced Friday.

The munitions were first found through a survey of the areas by deep-water vehicles with sonar and video cameras on board back in April, the Scripps Institution of Oceanography at the University of California, San Diego, which led the survey, explained via email.

The region was known for being a government-approved industrial and chemical waste dumping ground from the 1930s until 1972, when the Marine Protection, Research and Sanctuaries Act, also known as the Ocean Dumping Act, was enacted.

In 2021, a Scripps sonar survey using underwater drones located over 25,000 “barrel-like objects” on the sea floor off the Southern California coast near Catalina Island.

The objects may have contained DDT, an insecticide that was banned in 1972, and other toxic chemicals, which were found in marine mammals in the region, and linked to cancer in sea lions.

A Navy review will determine “the best path forward to ensure that the risk to human health and the environment is managed appropriately,” the military branch said.

With Post wires