The two people who were killed when their Asiana Airlines flight crashed were Chinese nationals, an official said.
Hayes-White also said that a number of passengers were seen emerging from the shallow waters of San Francisco Bay when first responders arrived on the scene.
However, the wreckage was a short distance away and Hayes-White said "the assumption" is that survivors may have immersed themselves in the shallow waters to douse flames.
Of 182 people transported to area hospitals, Hayes-White said that as many as 49 arrived in serious condition.
At San Francisco General Hospital, 53 crash victims were treated. At about 9 p.m., six were in critical condition -- five from an earlier wave and one new patient. A total of 15 people have been admitted to the hospital.
Sheriff Ross Mirkarimi said his department was beginning to escort passengers back to SFO, as the city was merely a transfer point for them.
Asiana flight 214 originated in Shanghai before heading to Seoul and then San Francisco. John Martin, director of the San Francisco airport, provided a breakdown of passengers' nationality: 77 South Koreans, 141 Chinese, 61 with U.S. citizenship, one Japanese and 11 from other countries.
Officials from the Chinese Consulate were visiting Bay Area hospitals to learn what they could about the condition of Chinese citizens on board, said Wang Chuan, a spokesman for the consulate.
"We are trying our best to help them," Wang said.
Wang said he did not know how many were injured or how extensively they were hurt.
San Francisco Mayor Ed Lee described a massive mobilization of airline workers, city staff and volunteers who served as Korean and Chinese translators, accompanied the injured to hospitals and provided grief counseling for survivors who gathered in the airport's red carpet club.
"Having visited the site with staff and police and the fire department, it is incredible that we have so many survivors but we still have many who are critically injured," Lee said, "and our hearts go out to them."
Lee said the investigation is firmly in the hands of the National Transportation Safety Board, whose chairwoman was expected to arrive in San Francisco shortly after midnight. A joint news conference will be held Sunday morning with airport and NTSB officials.