Changes have been made at Iowa’s maximum security prison in Fort Madison due to a dangerous drug getting into the hands of inmates.

The union that represents a majority of state workers claims there’s a rising drug problem at the Iowa State Penitentiary. AFSCME Council 61 president Danny Homan says the synthetic drug K-2 is making the rounds and a few inmates have been “near death” from overdoses.

Homan has long criticized what he calls “dangerous understaffing” of Iowa’s prisons. On Monday, in a news release, the Iowa Department of Corrections confirmed the presence of synthetic marijuana within the walls of the state pen and announced “changes in procedures to intercept the contraband.”

Corrections spokesperson Lettie Prell declined to elaborate, citing “security reasons.”