An estimated 188.5 tons of unwanted or expired prescription medications were collected around the country on the third National Prescription Drug Take-Back Day on October 29, the Drug Enforcement Administration (DEA) announced.

The DEA has collected almost 500 tons of medications since it began the program 13 months ago, according to the Associated Press. More than 5,000 drug collection sites were set up around the country for the latest event.

“The amount of prescription drugs turned in by the American public during the past three Take-Back Day events speaks volumes about the need to develop a convenient way to rid homes of unwanted or expired prescription drugs,” DEA Administrator Michele M. Leonhart said in a news release.

According to the DEA, studies have found the majority of teens who abuse prescription drugs get them from family and friends for free, including from household medicine cabinets. “Many Americans simply do not know how to properly dispose of their unused or expired medicine, often flushing it down the toilet or throwing it away. These methods can pose both safety and environmental hazards,” the news release noted.

Last week, the Centers for Disease Control and Prevention published a report that found the number of Americans who died from overdoses of prescription painkillers more than tripled in the past decade. More people now die from painkillers than from heroin and cocaine combined.

An estimated 14,800 people died in the United States from painkiller overdoses in 2008, a more than threefold jump from the 4,000 deaths recorded in 1999, the CDC said. Prescription and illegal drugs caused 36,450 deaths in 2008, compared with 39,973 deaths from motor vehicle crashes.