Dense fog was blamed for a string of accidents on the 21st South freeway Thursday about 8:30 a.m. that involved four semitrailer trucks, three pickup trucks, a van and eight cars.

The fog reduced visibility to about 300 feet, at best, some of the accident victims said. Heavier patches of fog reduced the visibility to less than 25 feet. Westbound traffic was restricted and eastbound traffic routed off the freeway while officers investigated the accidents.A 16-year-old girl, who was a passenger in the van along with eight other students, and a 32-year-old man and a 57-year-old man, who were drivers in separate vehicles, were hospitalized. Utah Highway Patrol troopers investigating the string of accidents could not confirm the identities of the three injured people while at the accident scene.

Nursing supervisors at LDS Hospital, Pioneer Valley Hospital and Holy Cross Hospital said none of the accidents was life-threatening.

Wes Jensen, who was treated at the scene for a cut on the chin, said he was on his way to work when the fog started closing in about 72nd West. He saw the profile of a semitruck blocking both eastbound lanes in front of him and was trying to stop when he hit something. "I couldn't even see what it was." There were no cars close to his when he got out to look around.

More than a half hour passed before Jensen learned he hit another car that later pulled off the road to avoid being hit again.

The truck Jensen saw had pulled out of the parking lot of Rocks Service & Country Store at 6381 West and was blocking both eastbound lanes when the chain reaction of accidents started. The string of accidents stretched a quarter mile west from there. Two semitrucks in the middle of the wreck had jackknifed in the median and the fourth became stuck on the shoulder of the road while trying to get out of the path of collisions.

Paula Tygersen said she had started to slow down because of the fog when she saw a car had crashed into the rear axle of the large truck. "I started to slow down, then the blue car hit me," she said. The next thing she knew there were cars crashed into hers on three sides.

In other parts of the Salt Lake Valley, low visibility because of the fog kept drivers from seeing five deer that were hit and killed in separate incidents on Victory Road, I-215 and Wasatch Boulevard.