(CNN) -- They were civilians and contractors, just starting their day at a massive military compound that's normally a bastion of safety.
But for reasons that may never be known, a former Navy reservist cut their lives short when he went on a shooting rampage at Washington's Navy Yard on Monday. Twelve families were left anguished.
About 3,000 people work at the Naval Sea Systems Command, and the Navy secretary said Monday it could take a full day before everyone is accounted for.
Jacqueline Alston hadn't heard from her husband, Ernest, who is a custodial worker there.
"Right now, I'm asking God to let me hear that voice, to let me see that man again."
• Michael Arnold, 59, of Lorton, Virginia;
• Sylvia Frasier, 53, of Waldorf, Maryland;
• Kathy Gaarde, 62, of Woodbridge, Virginia;
• John Roger Johnson, 73, of Derwood, Maryland;
• Frank Kohler, 50, of Tall Timbers, Maryland;
• Kenneth Bernard Proctor, 46, of Waldorf, Maryland;
• Vishnu Shalchendia Pandit, 61, of North Potomac, Maryland;
• Arthur Daniels, 51, of Southeast Washington, D.C.;
• Mary Francis Knight, 51, of Reston, Virginia;
• Gerald L. Read, 58, of Alexandria, Virginia;
• Martin Bodrog, 54, of Annandale, Virginia;
• Richard Michael Ridgell, 52, of Westminster, Maryland.
At least eight others were also injured, Washington Mayor Vincent Gray told reporters Monday night.
Three were shot, including a woman who was struck in the head but miraculously survived. The bullet did not penetrate her skull.
The others were hospitalized for contusions and chest pain.
Among the injured is Washington Metropolitan police officer Scott Williams, who underwent surgery Monday afternoon for gunshot wounds to the lower legs.
Doctors will try to determine Tuesday whether he'll be able to use his legs again.
"He was most concerned about being able to talk to his mother and wanted to make sure he was able to speak to her before he went into surgery," said Dr. Janis Orlowski, chief medical officer at the MedStar Washington Hospital Center.
Wounded survivors are eligible for treatment at a U.S. military' hospital, just as if they were soldiers wounded in war.
U.S. Navy Secretary Ray Mabus said that Walter Reed National Military Medical Center in Bethesda, Maryland, is open to them.
Amid the tragedy, tales of survival and heroism emerged.
A maintenance worker who tried to warn others was among those shot, said U.S. Navy Cmdr. Tim Jirus.
Jirus was standing in an alley at the bottom of a fire escape supervising the evacuation of Building 197 when the shooter approached him.
"(The maintenance worker) walked up and told me that he heard that there was a shooter in our building," Jirus said. "And we were just standing there maybe three feet away having a conversation, and then we heard two more gunshots, and he went down and that's when I ran."
Jirus said he did not know the man. He was "fairly certain he is dead, because he was shot in the head."
"I don't feel lucky that he got hit instead of me, but I feel lucky to be here," Jirus said.
Witness: 'He aimed his gun at us' and fired
People who want to check on family members who may have been at the Navy Yard can call one of two numbers: 202-433-6151 and 202-433-9713.
CNN's Chris Lawrence and Jonathan Auerbach contributed to this report.