6 Students Injured by Debris Left at Beach : Hazards: Beach officials say sharp metal was left in water from filming of “The Flash” TV show. Warner Bros. says the area was cleaned up.

In the comic book, the Flash left in his wake a whistling wind and a gallery of rogues.

In San Pedro, where a television show based on the comic book “The Flash” was filmed this week, he bungled. While zipping across the water at Cabrillo Beach, he apparently left behind sharp metal props that sent two schoolchildren to the hospital.

Though Warner Bros. disputes his account, the beach’s senior ranger, Tom Kotter, said a special effects crew for “The Flash” staged a series of explosions at the beach on Monday and did not clean up all of its mess. The debris was still in the water Tuesday when several busloads of schoolchildren from Long Beach Adventist School arrived for a year-end outing, according to Kotter.

“It looked like any beach,” said Principal George Newmyer. “The kids got in the water and were playing and then we heard screaming. Everyone gathered around and wondered what happened.”

Two students were taken to area hospitals for stitches. Lifeguards treated four others for minor cuts and scratches. Students, as well as the parents and teachers who chaperoned the trip, were angry when they were told by lifeguards that the debris was from a special effects shot for a television show.

Donald Armstrong, the parent of a third-grader who required 20 stitches, asked: “Why would the company do this, and why would the city allow this? This was supposed to be a public beach.”

Warner Bros. spokesman Doug Buitsman said he is not convinced that the company left anything behind from its Monday evening shoot. The special effect used plastic stakes to secure a line of explosive charges, which were set off one after another to simulate the Flash dashing across water, he said.

Before moving on to another filming location Tuesday, Buitsman said, “We cleaned the area thoroughly.”

The section of beach was shut down by lifeguards after the injuries Tuesday and for part of Wednesday. After being contacted by city officials, the movie crew hired a diver to return to the site Wednesday to clean up again.