Crumb rubber is toxic. It contains cancer-causing and illness-causing chemicals. It's rubber ... it's chemicals. It's stuff we don't even know the impact of. The tire industry has pulled a major fast one ... here, pay US to buy our toxic waste! Gee, we had to pay to dispose of it before ... now you pay US to buy it! What a deal! 

Insanity, absolute insanity, to have your kids roll in this stuff, breathe it in, eat it ... it contains chemicals ... cancer-causing chemicals. What else do you need to know? 

"Is it safe to roll around in cancer-causing stuff?"

Hmm. Yes, latest study is 'yes it's safe!' ... lol ... where did our critical thinking skills go?