Trying to save kids in hot cars

After small children were killed by powerful air bags in the early 1990s, the federal government issued a recommendation -- put all babies in rear-facing carriers in the rear seat and put young children in the rear seat, as well.

Deaths dropped from a peak of 60 in 1995 to zero by 2002. The solution included a new generation of air bags. Mission accomplished.

But there was an unintended consequence. Parents somehow began to forget they put their babies in those rear-facing seats. And when these kids were left trapped in cars parked in the sun, they were handed a death sentence.

Child deaths from heat exposure doubled from 20 annually in the mid-1990s to 40 in 2004. Last year, the number stood at 35.

Everybody knows how hot a car gets parked in the sun, but few can appreciate how quickly the temperature accelerates.

Even on a day with moderate temperatures, a car's indoor air can reach more than 160 degrees. A car can heat up to a fatal temperature within 10 to 15 minutes on a hot day. Children have died in cars even on days when the outdoor temperature was as low as 70 degrees.

It's not just the air temperature that kills. Heat radiates from windows and other surfaces, raising the effective temperature for anybody stuck inside, said Larry Baraff, a UCLA pediatric emergency doctor.

Adults, of course, can get out. Young children cannot. As temperatures rise above 100 degrees inside the car, the cooling system of a trapped child is overwhelmed, Baraff said.

The human body sheds heat in two ways: radiating it off the skin and sweating. Because the human body runs an internal temperature of about 98 degrees, it cannot cool itself by radiation much above that. In a hot car, the reverse occurs. Dashboards and other surfaces can reach 200 degrees.

Evaporation does little to help. Babies are often shrouded in clothing. Until that clothing is soaked, there is little evaporative cooling. By the time a baby's core temperature reaches 106 degrees, death is near.

The solution may seem obvious: Parents should not leave their kids in the car. "Personal responsibility" advocates would put the onus on these parents and argue that the government should not play a role. Indeed, some readers of last week's column on this issue have contacted me to say they don't want to have to pay anything for a safety system to prevent such deaths.