Those chains are pretty chemically inactive, but the trouble comes when unreacted BPA molecules stick around in the plastic.

这些链条的化非常不活泼，但当未反应的 BPA 分粘在塑料中时，题就来了。

For instance, any unreacted carbon atoms from the logs form little clumps of soot that rise into the flames and emit the yellow-orange light we associate with a campfire.

例如，木中任何未反应的碳会形成小块烟灰，这些烟灰会升入火焰并发出我们与篝火相关的橙黄色光。