Rescuers found the body of James Zell, 64, of Westland, about 7:15 p.m., and authorities notified his family, Zech said. Zell was a salesman at the store, located about 15 miles from Detroit.
"We suspected somebody was in the office area. The dog hit on it," said Shawn Bell, Wayne's deputy fire marshal. Bell said as of 7:45 p.m., about 30 percent of the site had been searched.
Zech said the missing woman, a clerical worker for the store, was still missing but rescuers were believed to be close.
The massive blast about 9 a.m. at the William C. Franks Furniture store was felt miles away. The owner, Paul Franks, was pulled from the rubble earlier and was in critical condition at the University of Michigan's medical center in Ann Arbor.
Police evacuated homes and businesses near the store in Wayne's business district. Officials expected all residents would be able to return by the end of the day.
Groups of firefighters entered the building four and five at a time, scraping away at the rubble using long poles with hooks on the end. Bobcats and front-loaders moved around the area. Video footage shot from TV helicopters showed dozens of rescuers working on and around the remains of the store.
Consumers Energy spokeswoman Debra Dodd said the utility believed natural gas was involved. The company had received a call of a possible gas leak in the area several hours earlier and a worker had been trying to track down the source when the explosion took place, Dodd said.