An explosion that could be felt blocks away injured two brothers who authorities believe were trying to make fireworks in a maintenance building at an apartment complex.
The men in their 30s, whose names weren't immediately released, were in critical condition following the Fourth of July blast in Oakland County's Independence Township, located about 30 miles northwest of Detroit.
"Obviously something went wrong, we're not sure if it was static electricity or they did something else stupid," Sgt. Kevin McCall of the Oakland County Sheriff's Office told the Detroit Free Press.
One man was taken to a Flint hospital, The Detroit News reported. The other man was taken to a Pontiac hospital.
"It shook the whole apartment," said Lauren Deighton, who lives in an apartment on the opposite end of the complex, told The Oakland Press of Pontiac.
Wednesday's explosion was under investigation. Authorities believe the men were using explosive powder to build fireworks.