Concern is due to the fact that fluoride is "one of the most important ingredients in toothpaste, helping to strengthen tooth enamel and prevent decay."
It doesn't officially have to be 'summer' for it to get hot in Texas. On any typical day it can get hot and can kill kids and animals that are locked in cars with the windows up. The message is repeated over and over again when it comes to kids or animals being locked in a car with the windows rolled up on a hot day. They can die from heat exhaustion in this situation.