Transcript for Yosemite Fire Blankets Communities in Unhealthy Smoke
massive california wildfire threatening yosemite park. And new concerns and dangers for the san francisco water supply. Neal karlinsky reports from the fire line right now. Good morning, neal. Reporter: George, good morning. If there's one word to describe this fire, it's stubborn. And we can all smell it in the air and feel it in our lungs. It is all this smoke, making life miserable for everyone here. An all-out war against this fire has so far kept communities largely safe from the massive flames. But the same people have been drenched in unhealthy smoke nor a week now. The first few days of school, canceled. What some are calling smoke days. The secretary called us and told us no school until wednesday. I think we were glad because our house is so smoky, they can't stay in it. Reporter: Sisters riley and lucy, haven't just been kept home but indoors. My throat, hurts my throat really bad when I breathe. It hurts my eyes. Reporter: Nasa is flying a research plane over the fires to collect air samples. A smoke plume so huge, it can be seen from space. There's fear that what can be seen in the air may be sneaking into the water. Public utility workers in san francisco are monitoring the city's water supply around the clock. Worried it will be polluted by ash because most of san francisco's water comes from this reservoir near the fire. So far, they say, instruments which detect particles in the water have not found anything unsafe. And that the water supply will be switched to nearby reservoirs if it gets bad enough. Firefighters are now finally turning optimistic. The fire overnight is 20% contained. That is huge progress in just the last 48 hours. George? Good to get that good news. Neal, thanks very much.
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