Plutonium: It's literally in our crap. Thank the National Institute of Standards and Technology, which admits that as much as 16 percent of the plutonium it spilled during botched research on "dirty bombs" a year ago at a building in Boulder probably made its way into the sewer system. Investigators, who have not yet recovered anything resembling a glowing rat, now tell Boulder city manager Jane Brautigam that there is no hazard to local residents, according to a letter  cited by The Denver Post . "Measurements conducted by a contractor hired by the City of Boulder with funds from NIST detected no radioactivity significantly different from natural background levels at several points within the sewer system, at the wastewater-treatment facility and in the sludge diverted from the sewer system." The letter continues, "we again acknowledge that this discharge should never have occurred." On June 9, 2008, a glass vial brimming with plutonium isotopes ruptured and a researcher was contaminated with radioactive particles, spreading them beyond the workplace and into the sewer system, probably when he washed his hands in a sink. NIST elaborates on the spill in a press release : "On June 11 two more personnel at NIST identified themselves as being potentially exposed to the powder in addition to 22 people originally identified; however, testing so far has shown no contamination of these additional individuals."