The Malibu Fire passed through the former site of the Santa Susana Field Laboratory, which was a military nuclear reactor testing site in the 50s and 60s. They managed to melt down a few test reactors in their day, also dumped radioactive and chemical waste on the premises. This kind of stuff doesn’t go away fast, though the worst substances like I-131 decay fairly quickly.
California government claims the air quality is fine, but the government also claimed the air quality was fine in downtown NYC after 9/11…
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