Four "good kids" are dead, the apparent victims of asphyxiation from inhaling laughing gas in a storage area of a dentist's office.

However, Cedar City police on Tuesday morning had not been notified by the state medical examiner of the exact cause of death.The bodies of Owen Mark Gregerson, 18, and Shawn Williams, 19, both of Cedar City; Christine Cherie Miller, 20, Fillmore; and Margaret J. Probert, 20, Scipio, Millard County, were discovered Monday when police and the Iron County attorney's office investigated the accident at 747 Paradise Canyon Road, the office of Ned O. Gregerson, father of one of the victims.

Iron County Attorney Scott Burns said the nitrous oxide was used by the dentist.

"They're all good kids, and it's a tragic loss for the community," Burns said.

It's not the first time in Utah the gas has been used "improperly," according to an official of the Utah Dental Association.

Dr. Jack K. Rasmussen, a West Valley City dentist and member of the association's House of Delegates, said there have been incidents in Utah of dental office employees and even doctors themselves using it improperly. There have been deaths in physicians' and dental offices from unsupervised employees administrating the gas to themselves.

"Unsupervised use of it can be deadly when it is self-administered - even by those trained to administer the gas," Rasmussen said. "Once a person is under its effect, there is no way to monitor it."

However, Rasmussen noted that nitrous oxide is the oldest and safest anesthesia available and has gained popularity in dental offices during the past 15 years. Patients, he stressed, should not be concerned about receiving the gas in an office where the physician has been properly trained.

To ensure its safe use, the Division of Occupation and Professional Licensing, Department of Business Regulations requires dentists to have extensive training in administering the gas. They have to obtain a special permit to use it. "You just can't graduate from dental school and go out and use it," Rasmussen said.

Physicians and nurse anesthetists also use the anesthesia, as do veterinarians on some occasions.

Nitrous oxide is used extensively in dentists' offices to relax patients and make time pass quickly. It does not eliminate pain but reduces anxiety and fear.

Rasmussen said people respond differently to nitrous oxide, just as they do to any drug. Therefore, the gas, administered with oxygen in the doctor's office, is closely monitored.

"Patients are always regulated to a point of where they are able to respond to the doctor," he said.

"It's very dangerous and has to be administered by someone who knows the complications and knows how to monitor it," stressed Ann Peterson, state licensing coordinator.

Rasmussen said, "The problem with nitrous oxide is that it competes with oxygen, and if you are in a closed area with no oxygen being supplemented, it can be deadly."

People using the gas unsupervised can go so deep into anesthesia that they suffocate and die.

That's apparently what happened to the Cedar City youths.

Burns said the tanks were turned on long enough to cause the deaths. The bodies, which were discovered just before noon Monday, were examined by the state medical examiner to determine the actual cause of death.

Burns said at a press conference that the four have no police records and have not been in trouble with the law.

The two young men were last seen Sunday night at 10:30 and had plans to meet the two women, according to Burns. He said the four were found by employees of the office building when they entered the storage room where the nitrous oxide tanks were stored. He indicated there was no evidence of forcible entry but added authorities are ruling the deaths accidental and ruled out suicide.