The family of a New Jersey hiker who died of thirst during a survival course sued the school and its guides Friday, claiming negligence in a risky expedition in the hot Utah desert.

Dave Buschow, 29, showed signs of extreme distress but was not offered emergency water by staff during the second day of a 28-day expedition in which 12 campers had few essentials last July. He died of dehydration.

The Associated Press this week detailed how Buschow was desperate and delusional in 100-degree weather long before he collapsed.

Buschow's parents, Patricia Herbert of River Vale, N.J., and Brad Buschow of Tafton, Pa., sued Boulder Outdoor Survival School and four employees, including Shawn O'Neal, the guide who was with Buschow when he dropped less than 100 yards from a pool of water in Garfield County.

The lawsuit filed in federal court in Salt Lake City seeks unspecified financial damages.

The employees "had actual or constructive knowledge of the risks associated with hiking in hot temperatures with limited supplies of food and water," the lawsuit said.

The Colorado-based school, known as BOSS, has denied any negligence and instead blamed Buschow, saying the security officer and former Air Force airman did not read course materials, may have withheld health information and may have eaten too heavily before arriving for the grueling course.

BOSS filed a lawsuit in the same court in January, asking a judge to uphold liability waivers signed by Buschow when he applied for the course. There has been no progress in that case.

"Mr. Buschow expressly assumed the risk of serious injury or death prior to participating," the school's lawsuit said.