A Coos County man who suffered burns over nearly half of his body in a “flashback” gas-can explosion has filed a $13 million lawsuit against Walmart, which he alleges sold him a dangerous fuel container, the manufacturer of which went out of business amid a wave of costly litigation linked to the product’s design. The plastic can produced by Blitz USA burst and sprayed burning fuel onto Daniel Rowlett as he poured a gasoline-diesel mixture into a burn barrel while trying to start a fire on Oct. 21, 2013, according to the suit filed Thursday in U.S. ­District Court in Eugene.