But nobody really knows, and because the agency has been getting contamination alerts from manufacturers for only a few months, it has yet to work out precisely how to handle them.
"Certainly, on a commercial-scale crop, over time, you are going to get contamination," said Doug Gurian-seniorn, scientistientist at the Union of Concerned Scientists.
"In some places somebody will read that information from inside the ward to somebody outside the ward and then that piece of paper is destroyed so you never get contamination.
You've got some contamination in your system.' " NIST was obliged to issue a correction to the U.S. mass scale, and to recalibrate all high-precision kilogram weights in the country.
Or the description at least, where it's perhaps somewhat unlikely that you would get a contamination.
"I'm keeping my fingers crossed we don't get any contamination," says SNO associate director Davis Earle.
And then there are the direct action community-based efforts, like getting radium contamination cleaned up in four suburban communities.
Make the packaging perfect, and you've still got [contamination] coming from further up the supply chain".
The experts said the DNA could have got there by contamination.
The defence had claimed that the material got there via contamination, but this was rejected by the jury.
They added that a trace of Sollecito's DNA on Kercher's bra clip, the vital piece of evidence linking him to the murder scene, could have got there by contamination, as the defence team said at the trial.
