ALDAN, Pa. (CBS) — Authorities are investigating how two sewer company workers died after passing out in a manhole in Aldan, Delaware County on Thursday. The victims have been identified as Daniel Cleaver and 20-year-old Matthew DiSands, both of Prospect Park.

UPDATE: the identities of the 2 men found dead in a manhole have been released. Daniel Cleaver, Prospect Park PA and Matthew DiSands, 20, Prospect Park were both pronounced dead at the scene. Police believe they may have been overcome by gas in the sewer while doing a dye test. pic.twitter.com/RjtK3v8cRZ — Kimberly Davis CBS3 (@KimberlyDavisTV) July 11, 2019

It happened at West Rively and South Sycamore Avenues.

BREAKING: Two men are dead after passing out in a manhole in Aldan, Delaware County. First responders attempted to rescue the men, but it was too late. @CBSPhilly pic.twitter.com/Qy5b6NuJKp — Kimberly Davis CBS3 (@KimberlyDavisTV) July 11, 2019

Aldan Borough Police Chief Ken Coppola says DiSands and Cleaver, who worked for A to U Sewer Services, were found 30 feet down in a sewer hole. Coppola says it appears the victims were overcome by gas fumes, but the medical examiner’s office will perform an autopsy to determine a cause of death.

Hazmat crews are on the scene.

Coppola says four workers were conducting a dye test in the sewers. Two workers were at Magnolia and Sycamore while DiSands and Cleaver were at Rively and Sycamore. When the two men at Magnolia were not getting a response from them, that’s when they learned that the victims had somehow lost consciousness.

By the time first responders were able to reach DiSands and Cleaver, it was too late and they were pronounced dead at the scene. It’s unclear how long they were unconscious in the manhole until help arrived.

UPDATE: OSHA is at the scene where two men died in a manhole. Their identities are being withheld at this hour. The two were in their early 20s. We’re told they worked for A to U Sewer Services. Investigators say gas may have caused the 2 to lose consciousness. @CBSPhilly pic.twitter.com/lecou3EeNM — Kimberly Davis CBS3 (@KimberlyDavisTV) July 11, 2019

The police chief added that there is no impact to the community.

The father of one of the victims is a police officer in Delaware County.

“It’s a very heartbreaking situation we got going on here,” Aldan Mayor Carmen Maniaci said.

Nearby residents knew something was wrong when they saw the large police presence.

“I figured because people were outside crying but we were just hoping it was because they got them up and out but it’s sad,” Chantel Tomasella said.

OSHA is investigating the incident.

CBS3’s Kimberly Davis contributed to this report.