John Stossel is a libertarian type who somehow got on television. A pleasant anomaly, like Brit Hume.
He's been taking on teachers' unions and public school ineptitude. In this piece, he points to the dire scientific warnings of yesteryear, such as the "crack baby" scare.
More important, he provides an explanation. Alarm generates cash. "This is not a big deal" generates yawns. Hence a bias for alarm. We need to correct for the bias in reading reports of global warning, bird-flu pandemics, and second-hand smoke. But we also need to remember that there really are emergencies and impending disasters.