As investigators continued to search for a suspect, those wounded in the incident continued to recover.
Boston-area hospitals had released at least 112 of the 178 people injured in the attack, according to CNN's tally late Wednesday. Of the 66 people who were still hospitalized, 13 were in critical condition.
Boston Medical Center has two patients in critical condition, down from 11 just after the bombings, Dr. Peter Burke, chief of trauma care, told reporters Wednesday. Ten patients are in serious condition and seven are in fair condition, he said.
Spectator Steve Byrne was standing with a group of friends near a mailbox when the second blast went off. Now his face is scarred with shrapnel wounds. A BB pellet remains lodged in his neck. Doctors said they couldn't remove it because was too close to nerves that control his vision, but he was out of the hospital on Wednesday.
Compared to how his friends are suffering, he told CNN's AC360 that he feels lucky.
Four out of the five friends he was watching the marathon with have lost limbs, he said. One friend had 70 nails in his leg.
He remembers the explosion in vivid detail: the blast that was so strong that it burned his clothes off; the carnage around him; and the haunting, slow-motion daze of searching for his friends.
"We were having a great day and waiting to see our friend cross the finish line," he said, "and then all of the sudden it turned in a flash."
He told CNN he's worried about the financial burdens his friends could face as a result of the explosion.
One friend is a carpenter and "both his hands are incinerated. He can't go to work, and the bills keep coming in."
"It's not just the hospitals. It's everyday life that doesn't stop. ... We're just hoping the mayor, the governor, President Obama don't let us as citizens down."
Beyond those seriously wounded, the incident affected thousands, including Candace Rispoli, who was cheering on a friend when the festive atmosphere turned into a "terrifying hell." She suffered minor injuries.
"I personally will never participate in an event of this nature in a city in fear that something like this could happen again," she said. "I keep replaying the moments of terror over and over in my head and am just still in utter shock. Always seeing terrible things of this nature happen all over the world on TV, my heart would always go out to those directly affected. But I never imagined in a million years I would be a spectator at the Boston Marathon running for my life."