MINNEAPOLIS (AP) — An 11-year-old boy who was overcome by fumes at a western Minnesota grain silo has died, becoming the third victim to die from the farm accident.

Authorities say Alex Boesl was pronounced dead on Friday. The boy had been hospitalized at Children’s Hospital of Minneapolis since breathing in the silage gas last Saturday.

The boy’s father, 47-year-old Curt Boesl, and uncle, 49-year-old Steven Boesl, also died.

Curt Boesl and his son Alex were working on top of the silo near Millerville when they apparently were overcome by fumes. Steven Boesl tried to rescue his brother and nephew and also was overcome.