My Chemical Romance's Bob Bryar Had Nitrous Oxide Canisters Next to Body

Bob Bryar -- the drummer for My Chemical Romance from 2004 to 2014 -- died next to a large supply of nitrous oxide ... according to the medical examiner.

TMZ obtained the autopsy report from Bob's November death in Tennessee, and the Bedford County Medical Examiner says the rocker's badly decomposed body was found next to three large nitrous oxide canisters.

The ME says antidepressant medication was also found at the home where Bob was found dead. The report notes the nitrous oxide canisters had attached tubing -- meaning they were ready for use -- but the ME stops short of saying the substance played a role in Bob's death.

In the autopsy, the medical examiner raises concerns about an intentional or accidental overdose ... but says Bob's body was so badly decomposed it's impossible to determine an exact cause of death.

TMZ broke the story ... Bob was found dead in his Tennessee home Nov. 26 and was last seen alive Nov. 4.

The autopsy describes how Bob's body was decomposing when he was found -- and notes significant parts of his body suffered "animal scavenging activity," and the report states 2 dogs were found in the home at the time he was discovered. We'll spare you further gory details ... it's all pretty gnarly.