Much of the mercury came from the New Almaden mine located in the foothills of the Santa Cruz mountains west of San Jose. The mining polluted the Guadalupe river with high levels of mercury. The river, which flows into San Francisco Bay, polluted much of the bay with methylmercury. To this day, many decades after mining stopped, the river and the bay are still contaminated with mercury to a degree where consuming fish and seafood from the bay can still be unhealthy.

Adobe, Google, Facebook, etc. are all right there on the shoreline. You might work in software, but (metaphorically at least), you're a lot close to those mines than you might think :)