The McDonald's Hot Coffee Case. In 1992 a women was burned from coffee purchased at McDonald's. She was a passenger in a car and after purchasing the coffee she placed it between her legs. When she removed the lid to add sugar, she spilled the entire cup.
You can read about the story in the link provided. So, how hot does fluid need to be to cause a burn?
"Each year, approximately 3,800 injuries and 34 deaths occur in the home due to scalding from excessively hot tap water. The majority of these accidents involve the elderly and children under the age of five."
"Most adults will suffer third-degree burns if exposed to 150 degree water for two seconds. Burns will also occur with a six-second exposure to 140 degree water or with a thirty second exposure to 130 degree water. Even if the temperature is 120 degrees, a five minute exposure could result in third-degree burns." (Source)
Moral of the story - as we tell our son - PAY ATTENTION!