NORTHFIELD, MINN. ? The police chief in Northfield who riled up the small city after asserting that hundreds of teens there were on heroin is leaving to become police chief in Emporia, Kan.

Gary Smith said the move is not related to the furor after a July 3 news conference at which he said 150 to 250 young people were using heroin or a related narcotic.

Some residents of this city of 18,000 questioned that idea, and within two weeks of his comments, Smith abruptly started a medical leave of absence and had not returned.

Smith’s comments in July dismayed Northfield school officials. Superintendent Chris Richardson said the district’s data on student drug use showed that during the 2006-07 school year, 15 students who were using heroin or oxycodone were referred for treatment.

Smith said he was not run out of town. He said he applied for the Emporia job in August.

“This was a family decision we made some time ago,” he said. “Nobody asked me to leave.”

After Smith’s heroin comments, the school district helped organize community events called “After the Headlines,” including a workshop on drug awareness. School officials also called in drug-sniffing dogs to search the high school this fall. The building came up clean, Richardson said.

The district has also doubled its chemical dependency counselor’s hours from one day a week to two, although that was planned before Smith’s comments, said Northfield High School principal Joel Leer.

The chief’s comments fixed the community’s attention on heroin, deflecting attention from other drug issues, Leer said.

Smith said the Emporia police department is about twice the size of Northfield’s. He said his new department knows about the heroin news conference and his health issues. He said he has undergone three surgeries this fall, two for sleep apnea and one to relieve numbness in his hands.

He starts his new job Jan. 7.