An employee worked in a degreasing operation where a solvent mixture containing three solvent ingredients $($A$,$ B and C$)$ was used. The personal air sampling suggested the exposure concentration of $250$ ppm from solvent A$,150$ ppm from B and $20$ ppm from C$.$ The PEL for solvent A is $500$ ppm TWA, and $200$ ppm for B and $50$ ppm for C$.$ Please calculate the equivalent exposure of the mixture, and conclude if the employee was overexposed? Hint: OSHA formula Em $=$ C$1/$L$1+$C$2/$L$2+...+$Cn$/$Ln$.$

total exposure $=0\mathrm{.}56$; the employee was overexposed.

total exposure $=0\mathrm{.}56$; the employee was not overexposed.

total exposure $=1\mathrm{.}65$; the employee was overexposed.

total exposure $=1\mathrm{.}65$; the employee was not overexposed.