FORT WORTH – The Tarrant County medical examiner's office confirmed Friday that the deaths of two people in July resulted from the drug "cheese."

Pedro Duque, 26, of Fort Worth died at his home July 7. The circumstances surrounding his death were not clear late Friday.

James Burnette, 17, of Arlington died July 31, three days before his 18th birthday. His parents found him slumped in a chair at home and he was taken to Medical Center of Arlington, where he was pronounced dead, police said.

The medical examiner ruled the cause of death on both as accidental, caused by a mixture of heroin and diphenhydramine, which is often found in over-the-counter cold medicine or sleeping pills.

The mixture is commonly known as "cheese" and is popular with kids as young as elementary age because it is relatively easy to obtain and inexpensive, less than $5 in many cases.

Tarrant County officials said that it would be next week before they could determine how many people have died from cheese there. Throughout the rest of North Texas, at least 23 people have died since 2005 as a result of the lethal drug combination.

Toxicologist tests are pending on several other cases that may also be cheese related.

On Monday, Paige Elliott, 16, died of an apparent overdose after being found passed out at a house in the 1400 block of Greenbrook Drive in Rockwall about 3:45 a.m. The Rockwall High School student was pronounced dead at Lake Pointe Medical Center.

Toxicology results from an autopsy are pending and the investigation continues. But Rockwall police spokesman Carl Alsabrook said that "based on our investigation, we suspect strongly that cheese heroin was involved and maybe other drugs. We are not sure what caused her death."

On Sept. 2 in Irving, 16-year-old Ana Rojas died from what authorities believe was a cheese overdose.

Her death prompted an informational meeting earlier this week involving Irving city officials and community activists to discuss the problem. After the meeting, Mayor Herbert Gears called for a task force of city employees and police and school officials to combat the drug's spread to inner-ring suburbs like Irving.

On Thursday, Tarrant County Challenge Inc., a 23-year-old agency that monitors drug and alcohol abuse, held a conference at Tarrant County College's South Campus to discuss the influence of cheese and how they can fight its expansion into that county.

Hundreds attended the conference including representatives with the Drug Enforcement Administration, local police departments and school districts and state authorities.

Arlington police said Friday that cheese had not been a problem in that city. Police spokesman Blake Miller said officers are aware that cheese has been an issue in other communities and have been actively looking for signs of the drug in Arlington. Until now, none had been identified.

Lt. Miller said homicide officers investigated James Burnette's death and said it appeared to have been an accidental overdose.

"This is Arlington's first death caused by cheese," Lt. Miller said. "Our investigators and all of our narcotics raids had not had cheese located or talked about."

Staff writers Richard Abshire and Brandon Formby contributed to this report.