The bag was first noticed by a contracting crew using miniature cameras to examine underground pipelines.
Responding police looked at the camera images and thought they saw a hand coming out of the bag.
Believing the bag may have contained a body, perhaps that of missing Jersey City prostitute Shannan Gilbert, two emergency workers descended into the hole to take a closer look. Gilbert's disappearance is what prompted the search at Gilgo Beach on Long Island that uncovered the work of a potential serial killer.
The emergency workers were equipped with oxygen packs before descending in the pipe because of dangerous underground gases.
They went 30 feet into the hole and quickly determined the bag was full of trash.
The emergency workers were pulled from the hole and are being evaluated.
The pipe examination was being conducted by Inframetrix, a company contracted by the Jersey City Municipal Authority. The contractor uses miniature cameras to examine pipelines in the city's older sections.