POSTVILLE (AP) - The dead man discovered in a flooded basement drowned after being overcome by carbon monoxide, according to a medical expert.

Bradley Brainard, 56, died Sunday in a home near Postville. His mother, Shirley Brainard, said he was pumping water out of the poorly ventilated basement.

The carbon monoxide buildup and cardiovascular disease contributed to Brainard passing out and drowning, said Michele Catellier of the state medical examiner's office.