Free radicals are normal and necessary to some degree. In addition to causing some damage, they also stimulate repair. It is only when so many free radicals are produced, and they overwhelm the repair processes, that it becomes an issue. That is what we call oxidative stress.
1 There were 178 fatalities in May (158 of those in the Joplin EF-5 tornado alone). 2  The record number of tornadoes during the month of May was 542 tornadoes set in May 2003.  The average number of tornadoes for the month of May during the past decade is 298.
10 deadliest U.S. tornadoes â 1.The Tri-State Tornado, which killed 695 people and injured 2,027, was the deadliest tornado in U.S. history, according to the National Oceanic and Atmospheric Administration.