California firefighters made a gruesome discovery over the weekend inside what they called a human-dug cave.

Two adult male bodies surrounded by a 'white powder substance' were found on Sunday morning in Northridge in the San Fernando Valley area of Los Angeles.

The white substance later tested positive for traces of fentanyl, officials said.

'Upon further discovery, we found a powder which, with the assurance of our hazardous material squad, we determined to have portions of fentanyl and were able to mitigate that and secure it, and we disposed of that,' said LAFD Chief Scott Hilton.

Firefighters made the finding while they were probing hazardous materials at an address for Pacifica Senior Living.

Two adult male bodies surrounded by a 'white powder substance' were found on Sunday morning in Northridge in the San Fernando Valley area of Los Angeles

A hazmat team was called to the scene, which is nearby a homeless encampment

The cave where the bodies were located was about two or three feet high, authorities said

After the white powder was found, a hazmat team was called to the scene, which is nearby a homeless encampment.

The cave where the bodies were located was about two or three feet high, authorities said.

The cave was close to train tracks and it appears individuals might have been living around it and dug into the ground

It appears to be part of the larger homeless encampment in the area.  

Police said the two victims were transients and are believed to have died of drug overdoses, as reported by ABC 7.

A medical examiner is yet to determine the official cause of death. 

DailyMail.com has reached out to the LAPD for comment on this story. 

Firefighters made the finding while they were probing hazardous materials at an address for Pacifica Senior Living

About 900 homeless people died on the streets of Los Angeles last year, according to City Controller Kenneth Mejia.

An analysis by the LA Times found that about 65 percent of the deaths were linked to drugs such as fentanyl and methamphetamine.

LA has around 46,260 homeless people, a number that is up by 80 percent since 2015.