DENVER -- Randi Bartling came across three syringes in the alley behind her home in the Alamo Placita Neighborhood.

Fearing for other people's safety, Bartling picked up the used needles with a plastic bag and threw them in a nearby dumpster.

"People just cut through here as a short cut. They walk their dogs like I do back here, "Bartling said. "It's just, you know, a lot of people are walking around here."

She said one of the syringes even had blood inside. Bartling took a picture of the needles and posted it on the neighborhood blog called Next Door. Other residents commented confirming the problem in the neighborhood.

Governors Park, just down the street from Bartling, isn't any different. Denver7 went to the park and spoke to Denver city workers.

"We find needles everywhere," said one worker.

"Like I said, the playground sometimes," another worker mentioned.

The two workers showed Denver7 a safety box where they store used needles. It sits in their truck. The workers told Denver7 they can find almost up to ten needles a day throughout the city.

Diseases may be carried with used syringes.

"Diseases like hepatitis B, hepatitis C, HIV," said Danica Lee.

Lee is the director of Denver's Environmental Health Department.

She encourages people to call 311 if you come across used needles.