(Adds details on incident)
By Alex Dobuzinskis
LOS ANGELES, July 5 (Reuters) - A major accident at an Independence Day fireworks show in Simi Valley, California, left dozens of spectators injured, police said on Friday, as suspicion fell on a collapsed launching platform as the cause.
"What we understand is potentially one of the launching stations fell over, resulting in ignited fireworks going into the crowd," Simi Valley police spokesman Sergeant Tom Meyer said.
There was no sign of foul play, Simi Valley police said in a statement.
Initially, police said 28 people suffered shrapnel wounds and other types of injuries in the resulting chaos; four of them were seriously hurt.
But calls to local hospitals revealed at least 35 people were hurt.
Shortly after the start late Thursday of the Simi Valley Rotary Club fireworks show about 30 miles (50 km) west of Los Angeles, fireworks landed in a crowd of 8,000 to 10,000 onlookers gathered on a soccer field, police said.
Officers in a helicopter took aerial photos of the scene of the incident on Friday to get a better sense of what went wrong, said Meyer.
The California Occupational Safety and Health Administration will be involved in the investigation, and Bay Fireworks of Bethpage, New York, which mounted the fireworks show, is cooperating with the probe, police said.
Simi Valley Hospital received 26 patients, said hospital spokeswoman Alicia Gonzalez. Those victims ranged in age from 17 months to 71 years old, with a dozen children among the injured, she said.
Injuries ranged from burns and shrapnel wounds to chest pains to trauma from being trampled by the crowd, Gonzalez said. Two people were at Simi Valley Hospital in fair condition on Friday, one person was transferred to an area hospital specializing in burns and the rest were released, she said.
A representative for Los Robles Hospital & Medical Center in Thousand Oaks said seven people injured in the incident were treated and released at the facility, and a spokeswoman for Providence Holy Cross Medical Center in Los Angeles said the hospital treated and released another two people.
Los Angeles station KABC-TV showed images of black fireworks debris spread all across the field where the show was staged.
This was the second year the local Rotary Club used Bay Fireworks for the fireworks show, police said.
Bay Fireworks said in a statement it "will conduct a thorough and complete investigation of this incident and make our findings available to the public."
In Seattle, illegal fireworks ignited a fire at a dryland boat storage facility on Lake Union, scorching 14 vessels and causing an estimated $1.4 million in damage, said Seattle Fire Department spokesman Kyle Moore.
The fireworks that caused the blaze appeared to have been set off from a recreational trail above the facility, he said. An investigation was under way, and authorities had not made any arrests in the incident. (Additional reporting by Ian Simpson in Washington and Elaine Porterfield in Seattle; Editing by Jeffrey Benkoe, Barbara Goldberg and Steve Orlofsky)