Two buildings owned by Google in Silicon Valley are being exposed to toxic vapors at the moment, according to a news report published today by CBS.

TCE, also known as trichloroethylene vapors, have been discovered at the technology giant’s QD6 and QD7 offices on North Whisman road.

A normal or safe TCE level is five micrograms per cubic meter, but CBS has reported that as much as eight micrograms have been found inside Google’s buildings.

The problem has reportedly arisen because the offices sit right on top of a site where Fairchild Semiconductor, Intel, Raytheon and other computer chip manufacturers used to operate.

During that period the firms allegedly took thousands of gallons of the toxic substance and disposed of it straight into the ground, contaminating the nearby water supply. It was eventually discovered in 1981.

When Google moved into “the Quad” in June last year, it set up state of the art filters and carried out air quality testing to ensure that the contamination didn’t become a problem. Today’s news, however, means that as many as 1,000 Google employees could have been exposed to TCE “for several months”.

The US Environmental Protection Agency (EPA) has reportedly said that it takes decades of exposure to TCE in order to cause any health problems.

Google has since released a statement, seen by CBS, which says: “The health and safety of our employees is Google’s number one priority, and we take several proactive measures to ensure the healthiest indoor air environments possible”.

Image Credit: KIMIHIRO HOSHINO/AFP/GettyImages