coronavirus July 29, 2021 6:47 am Silicon Valley Tech Companies Tighten Their Rules on COVID-19 Vaccinations Tech companies large and small are tightening their rules on vaccinations. Kris Sanchez reports. US & World Videos 5:57 San Francisco trying to ban cancer-causing chemicals in firefighter gear, but are alternatives safe? 1:53 5 sports icons inducted into the Bay Area Sports Hall of Fame 3:16 San Francisco mom highlights student safety on Muni after alleged anti-Asian attack 0:24 Murder suspect arrested following neighborhood lockdown in Antioch 2:50 Israel-Hamas ceasefire negotiations underway