In 1939, Paul Müller, an employee of the J. R. Geigy Company in Basel, Switzerland, was working on a method to kill clothes moths without damaging clothes. Müller stumbled upon Zeidler’s formula. What he found surprised him. Not only did DDT kill the moths, it also killed flies, mosquitoes, lice, and ticks—insects responsible for transmitting some of the world’s deadliest diseases. Better still, DDT’s killing power seemed to last for months.
And over those months you think it's doing nothing else to anything else?
