A 17-year-old Fairfax County high school junior died late Monday afternoon after inhaling a commonly available variety of silicone spray, according to Fairfax County police.

While the exact cause of death will not be determined for at least three weeks, Fairfax Hospital is listing Michael Sims' death as a "sudden death attributed to" inhalation of the spray.

Fairfax County and federal experts said yesterday that this is the first time they have heard of the "sniffing" of silicone, although there were at least four deaths and 308 hospital admissions around the nation between May, 1976, and April, 1977, attributed to the intentional inhalation of various kinds of sprays and vapors by young persons trying to get high.

Silicone spray is used primarily for two purposes - as a fixative by artists and as a lubricant. Fairfax County police would only say the spray is in the hand of a toxicologist and will be sent to Richmond for analysis," and refused to specify the type of spray used by the high school student.

Sims, who lived at 7922 Landing La., in Merrifield, was found by a friend in the woods behind the Jefferson Golf Course, on Pioneer Lane in Merrifield, according to police.

"He was attempting to get high by inhaling silicone spray and the spray caused cardiac arrest," police said.

According to a police spokesperson, Sims had been walking with a friend in the woods about a block from Sims home shortly before the incident. The friend left the woods, police said, and when Sims did not emerge a short time later the friend returned to the woods and found him.

According to a Fairfax Hospital spokeswoman, Sims was brought to the hospital by the Dunn Loring Rescue Squad at 4:52 p.m., who revived him and administered cardio-pulmonary resuscitation on the way. Sim's heart stopped for a second time in the hospital and he was pronounced dead at 5:25 p.m.

George Stepp, assistant principal of Falls Church High School, described Sims as a "very gregarious fellow. He had a lot of friends" at the school.

"He was easy to work with and didn't give you the impression that he had any problems. Socially, he seemed to be well adjusted and he was an average student," Stepp said. "He seemed to enjoy school. This was a shock to his friends and the community," the assistant principal said.

The inhalation of substances like glue and various aerosol sprays reached a peak in the late 1960s. A 1970 article in the Journal of the American Medical Association coined the term "Sudden Sniffing Death" to refer to such deaths.

There are two primary causes of death in cases involving spray inhalation: suffocation and heart arrythmia, a potentially fatal irregular heart beat. Both appear to be caused by the propellant - the gas or chemical used to carry particles of substances such as silicone, paint or cooking shortening - rather than the substances themselves.

While not everyone who inhales such sprays dies, there have been studies showing that chronic use of the sprays can lead to loss of memory and loss of ability to think clearly.

Persons who sniff the sprays from paper bags run a very real risk of losing consciousness and then suffocating, said Dr. Charles W. Sharp, a biochemist who heads a study of the problem at the National Institute of Drug Abuse.

With many of the sprays, he said, the user "goes into a feeling of being light headed, then into feeling really good, then into a depressed state, then into an anesthetic state and then death."

Another possibility, said Sharp, is that a persons' air passages may become anesthetized by the spray and close down, causing suffocation.

Some of the propellants, such as freon gas, can, in concert with the body's natural adrenaline, cause fatal irregularities, or arrythmias, in the heart.

This throws off the heart's electrical system and causes the organ to flutter, rather than beat regularly.If electric shock is administered in time the proper beat can often be restored; if not, the heart fails to circulate the blood and the person dies of suffocation.

There is little way of knowing, experts say, how much, or how little, spray will kill any given person.

Among the more commonly inhaled substances today, say drug abuse experts, are nitrite - usually used by heart patients as medication - glues and automobile transmission fluid.