Marich and Vazquez were working in a shipping container at Galaxy Granite, Inc. at 1525 Cortland Ave. when slabs of granite fell on them at 10:16 a.m., fire spokeswoman Mindy Talmadge said.
After the slabs fell, the two men were both extricated from the shipping container. Marich was pronounced dead at the scene while Vazquez was taken to San Francisco General Hospital, where he later died, Talmadge said.
The California Division of Occupational Safety and Health is investigating the accident, a Cal/OSHA spokeswoman said.
