The Morning Call newspaper reports an evacuation involving at least six Allentown residents Wednesday night.
WFMZ-TV says firefighters and workers from gas company UGI are on the scene and are digging into the street.
A spokesman for UGI hasn't returned a request for comment. The odor was reported about five blocks from the site of last week's explosion.
The blast sparked an inferno that burned for hours while crews tried to shut off the gas supply. A 16-year-old girl and a 4-month-old boy were among those killed. Eight homes were destroyed.
Neighbors say the blast knocked shelves off walls, brought down ceilings and ripped a front door off its hinges.