An Auckland woman should have passed the Boston Marathon finish line just as the blasts happened but believes a fall saved her life.
And her husband, watching her progress at home, spent a harrowing five hours not knowing if she was alive.
"I knew she was due to finish a minute before it happened, it was harrowing," said Bob Taylor.
His wife, Gail, 69, was 500m from the finish line when the blasts hit. She was tracking to pass the explosion site just a minute before, but minutes before that, she tripped and split her chin, forcing her to slow down. But the race was suddenly stopped.
A woman walking the other way told Mrs Taylor a bomb had gone off.
"I just went completely numb. It was terrifying. I had a friend, and I know she was ahead of us, but we didn't know what had happened to her," she told the Herald.
"It was just chaos, absolute chaos."
One man was panicking, thinking his legs had been blown off because his trousers had been burned. It was only once he'd calmed down that he realised they were still there.
Meanwhile, at their home in Whangaparaoa, Mr Taylor had no idea if his wife was alive.
His neighbours called to tell him about the bombings and to ask if Mrs Taylor was all right, but he didn't know. He couldn't eat or focus on anything, he just kept himself busy to distract himself from what might have happened and his step-daughter came round to keep him calm.
"The old heart was thumping like hell," he said. "I had a coronary bypass two years ago and it's the first time I've had to use Angi-Spray."
After five hours of silence, the New Zealand Consulate called Mr Taylor to let him know his wife was safe.
"If she hadn't fallen, she would have been right in the bomb zone. It was just horrendous."
Mrs Taylor was among 45 Kiwis runners in Boston.
They included athletes Nick Willis and Kim Smith who took part in a shorter event before the marathon and left Boston before the blasts.
Also among them was John Goold, who had just crossed the finish line and was getting a banana when he heard a thunderous explosion about 200m behind him.
A thick cloud of smoke blew across the street as white-faced people turned to each other, confused.
"An official told us it was a transformer blown up, but it was too big and after the second one, there was no doubt it was a terrorist attack," he said. "It was such a big explosion."
The deputy principal at Avondale College said everyone seemed eerily calm after the blasts and followed officials' instructions to head to a meeting place where he found his wife, Lynn. The public transport systems were shut down so they had to walk for two hours to their hotel.
"We moved very, very orderly and everyone was very calm. But all the sirens ... give people a bit of panic."
By last night the Ministry of Foreign Affairs had received no reports of New Zealanders hurt.
Key leads messages of condolence for victims
Prime Minister John Key led New Zealand messages of condolence to the families of those killed and injured in the blasts.
"Our thoughts are with the people of Boston at this time. We were all shocked to hear of the tragedy that has unfolded.
We are concerned for the people from around the world who participated in, and supported, the Boston Marathon."
The New Zealand embassy in Washington, supported by the New Zealand honorary consul in Boston, was liaising with local authorities to determine if any Kiwis needed help.
Forty-five New Zealanders registered to run the marathon. The Ministry of Foreign Affairs and Trade was working with Athletics NZ to make contact with the New Zealanders known to be in the area.
Labour Party leader David Shearer said the party sent its sympathy to the people of Boston.
He said it was a shocking event and his thoughts were with those involved.
Mr Shearer was concerned about the welfare of New Zealanders who were involved in the marathon and who were in the area when the bombs went off.
New Zealanders who have concerns about family or friends in Boston are advised to try to contact them directly. If they require further assistance they should call the Ministry of Foreign Affairs and Trade's consular division on (04) 439 8000 and ask to speak to a consular adviser.