SAN FRANCISCO (KGO) -- Numerous people are complaining about an odor of rotten eggs and sulfur in San Francisco. An investigation is underway near the Fairmont in Nob Hill to find the culprit.The smell was first reported around 2:00 a.m. Wednesday. PG&E has not found any gas leaks. The Chevron refinery in Richmond also investigated and did not find the cause. There has been some speculation that it was the earth releasing some smells because of the Nevada earthquakes.The Bay Area Air Quality Management District is investigating.There are no reports of anyone who needed to be hospitalized or was injured.