OLYMPIA, Wash. -- The parents of a boy who was killed by an exploding cannon at a Fourth of July celebration have filed a wrongful death lawsuit against Thurston County and Airlift Northwest.

The parents of the 8-year-old, Devan Vyborny, accuse medical responders of being poorly trained and wrongly canceling a medical airlift.

The Olympian reports a county spokesman declined to comment on the lawsuit filed Tuesday in Thurston County Superior Court.

Littlerock Deputy Fire Chief Gary Kerker previously said the crew responded in minutes and did everything it could.

The boy was struck in the chest by shrapnel when an 18-inch cannon fired by his grandfather exploded at the 2007 family celebration near Rochester.

The lawsuit, filed in Mason County, accuses medics at the scene of not knowing "which emergency devices to use on Devan," and failing to quickly get the boy to a hospital.

The family says in the lawsuit that two requests for an airlift helicopter were cancelled by 911 dispatchers, delaying Devan's treatment.