Chinese-manufactured fireworks malfunctioned at a July 4 fireworks show in Vienna, Va., rocketing into a crowd composed mostly of children, injuring 11 and sending at least seven to the hospital.

The show was proceeding as planned until the start of the finale when a cake box with 25 rockets fired the trajectories in many directions around the ballpark where the show took place.

That show was one of six in Fairfax County, Va., in which the same cake box misfired. However, it was only in Vienna where citizens were injured, Fairfax Fire Marshal spokesman Dan Schmidt said.

Schaefer Pyrotechnics of Ronks, Pa. operated all the shows in Fairfax County and has done so for 10 years. The company is not being blamed for the workmanship of the Chinese shells. Schafer representatives refused to comment.

The item being blamed in each misfire was the cake box, which is a container of five rows of five three-inch mortar tubes ignited by a single fuse. In all the cases, it appears one of the mortars exploded early, tipping over the container and sending the rockets screaming outwards just a few feet above the ground. One of those mortars narrowly missed two Schaefer employees at the Fairfax City show.

Schmidt said all the fireworks were carefully inspected, following the National Fire Protection Association regulations, and that the cake boxes had been secured by at least 600 pounds of sand bags.

Nearly 99 percent of all fireworks sold legally in the U.S. are imported from China, according to the American Pyrotechnics Association, a trade group that promotes the sale of fireworks.

The group also said that fireworks manufactured in China are more strictly inspected than other items such as toothpaste, which was recently discovered to have been manufactured with a poison used in antifreeze.

Witnesses described the scene to The Washington Post as chaotic.

Schmidt said in his 10 years in the Fire Marshal's office, he has never seen a professional fireworks display malfunction.

Marie Kilsner, a spokeswoman for the town of Vienna, said she believes that a woman in her '30s and her 3-year-old son are still being treated at northern Virginia hospitals. She said because of Federal privacy regulations she doesn't know any more details.