A federal team has arrived in Colorado to help investigate hospital reports that synthetic marijuana is to blame for scores of recent illnesses and possibly three fatalities in the state.

"The deaths are suspect, they're being investigated," Mark Salley, spokesman for the Colorado Department of Public Health and Environment, said Tuesday.

The five-member federal team from the Centers for Disease Control and Prevention includes experts trained in epidemiology and toxicology.

Salley said they will join investigators from the state and Tri-County Health Department trying to determine the source of synthetic pot - also known as "spice" - that apparently has sickened an estimated 75 people since late August.

The effort may take weeks, Salley said. He urged people not to ingest synthetic pot.

The outbreak in Colorado followed a case in North Carolina, where the U.S. Drug Enforcement Administration charged 30 people in July with conspiracy to distribute synthetic marijuana and other drugs.

"The rise of synthetic drug use in the United States alone has reached epidemic proportions and has resulted in a sustained rise in emergency room visits, deaths, and violence among teens and young adults," Harry S. Sommers, special agent in charge of the Atlanta field division of the CDC, said in July.

Wyoming last year saw a number of illnesses associated with synthetic marijuana. That outbreak sparked a CDC probe that found 16 people in six states had suffered kidney damage from the drug.

Wyoming authorities said more than a dozen people were sickened in the Casper area and several were hospitalized with kidney failure following exposure to synthetic marijuana.

Two women were recently sentenced to federal prison in Wyoming for distributing the drug and causing serious injury.

Dr. Tracy Murphy, Wyoming state epidemiologist, said Tuesday that the cases came to light last year after an unusual number of patients went to hospitals with kidney failure, back pain, abdominal pain and vomiting.

Murphy said substances sold as synthetic marijuana are unpredictable in terms of ingredients and physical reactions.

"There's probably lots of illnesses and harmful effects that we probably just don't know about yet," he said. "The best thing is that people just need to not put that stuff in their bodies."

Wyoming and other states, as well as the federal government, have attempted to outlaw synthetic marijuana. However, lawmakers face a moving target because the chemical nature of the substance can evolve.

Murphy said manufacturers may try to make new products based on what is or isn't outlawed.

A CDC report says synthetic marijuana appeared in the United States in 2009. It is generally comprised of a drug solution applied to plant material and is distributed globally "under countless trade names and packaged in colorful wrappers designed to appeal to teens, young adults and first-time drug users," the report states.

"Products are often packaged with disingenuous labels such as 'not for human consumption,' or 'incense,' but health professionals and legal authorities are keenly aware that these products are smoked like marijuana," the report says.