1. Researcher preparing cultures, zoom in to cultures
2. SOUNDBITE: (English) Dr. Richard Jackson, California public health officer:
"They used heat to kill the bacteria, and it looks like apparently it did not work. We are told that these are the only customers for this killed anthrax. We're going to have to investigate that further."
3. Various close shots of researcher using test tube and syringe
4. Biohazard sticker
5. SOUNDBITE: (English) Dr. Bertram Lubin, research director at Children's Hospital Oakland Research Institute
"There's always a risk, so we can't say there's no risk, but it's very, very, very low, and they understand this. And when you embark upon a career in research to try to develop vaccines, you recognise that sometimes things like this can happen."
6. Various of scientists in lab working with test tubes
7. SOUNDBITE: (English) Dr. Victor Hou, researcher
"You would think that they would have the proper screening and and would test the culture before they sent it out."
Officials at Children's Hospital Oakland Research Institute in California said on Thursday that at least six researchers developing an anthrax vaccine for children may have been exposed accidentally to live anthrax because of a shipping mistake.
The researchers thought they were working with dead anthrax bacteria until the mice they were using in experiments started to die.
A spokeswoman for the institute said none of the researchers has shown signs of infection since the first potential exposure about two weeks ago, but that as a precaution, each is being treated with a 60-day regimen of the antibiotic Cipro.
The anthrax was shipped from a Maryland laboratory to the San Francisco facility about three months ago.
Federal, state, and local officials - including the FBI - are investigating the mix-up.
Anthrax attacks carried out through the US postal system killed five people and sickened 17 others in 2001, prompting research into more effective vaccines and treatments.