(CNN) -- A spate of fireworks debacles and tragic parade accidents tempered Independence Day celebrations across the country.
The mishaps Thursday left 20 people hospitalized in southern California, two people dead in parades nationwide and more than $1.5 million in damage in Seattle.
Two people killed in parades
In Oklahoma, a 7-year-old boy on a parade float was killed when his father accidentally ran over him, Edmond police said.
The boy was on a martial arts float that was driven by his father, police spokeswoman Jennifer Monroe said. It's unclear whether the boy jumped or fell from the float before he was run over by the trailer's tires.
Another tragic parade accident took place in Bangor, Maine, when a man driving a tractor in the Independence Day parade died after a vintage fire truck struck him from behind, authorities said.
Bangor police Sgt. Paul Edwards said the parade had been rerouted because of a four-hour standoff with a gunman who fired several rounds at police from an apartment window.
The parade participants "would not have been on that street normally," Edwards said.
Fireworks shows gone awry
A fireworks display in Simi Valley, California, turned disastrous when fireworks apparently burst toward the crowd and injured 28 people.
At least 20 were hospitalized, including four who were moderately or seriously injured, said Capt. Mike Lindbery of the Ventura County Fire Department.
Witness Annisa Wynn told CNN affiliate KTLA fireworks suddenly began shooting sideways into the crowd instead of up in the air,
"The fireworks were so close, you could see them on the ground," Wynn said. "It never happens this way. People were screaming."
Another show in Windsor, Colorado, sparked flames that rose 10 feet high over parched land, witness Kami Gilmour said.
"The first embers dropped and looked like it might have started a small tree on fire," Gilmour said. "Then we realized there were six or seven fires all along the field, and then a gust of wind came and blew the fire all over the place. ... Our car was about 50 yards from it and covered in soot."
There were no immediate word of injuries from the Colorado fire.
Illegal fireworks destroy 14 boats
Seattle authorities said illegal fireworks sparked a massive fire that caused $1.5 million in damage.
A firework landed on a boat cover at a boat storage facility on the north end of Lake Union, Seattle Fire Department spokesman Kyle Moore said. Moore said the dry storage facility stacks boats four stories high.
Within seven minutes, the fire destroyed 14 boats.
Moore said Seattle also had three roof fires started by fireworks.
Boy shot at July 4 picnic
A 7-year-old Chicago boy picnicking with his family is in critical condition after he was shot in the neck, CNN affiliate WLS reported.
The boy was playing at Cole Park on the city's south side when two people fired and drove away, police said, according to WLS. Authorities don't have a clear description of the shooters or vehicle.
CNN's Jake Carpenter, Dave Alsup, Dottie Evans and Mayra Cuevas contributed to this report.
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