Google says it has fixed structural problems that were letting carcinogenic gas into a Mountain View office. According to the Mountain View Voice, two Google locations at the "Quad" campus on Whisman Road were found to have potentially dangerous levels of trichloroethylene or TCE, a carcinogenic solvent used by early Silicon Valley giants like Intel and Raytheon to produce chips. In the 1980s, environmental agencies found that TCE had contaminated the groundwater around the area, creating what's now known as the Whisman-Ellis -Middlefield (MEW) plume.

Google's buildings have come up clean before, but the EPA says they were recently found to have TCE levels above the recommended indoor level. That's likely because of recent building changes that allowed the vapors to seep inside. A Google spokesperson says that the problem was fixed quickly after being identified, and that "The health of our Googlers was not put at risk in any way at any time." While no company wants to admit to potential risks for its employees, that's backed up by an EPA official, who confirms that long-term exposure is the real threat. More than anything, it's a somewhat morbid reminder of how past decisions can have effects lasting decades into the future, even in the fast-moving tech industry.