A substance has a Threshold Limit Value $-$ Time Weighted Average $($TLV$-$TWA$)$ of

$200ppm,$ a Threshold Limit Value $-$ Short Term Exposure Limit $($TLV$-$STEL$)$ of $250$ ppm$,$

and a Threshold Limit Value $-$ Ceiling $($TLV$-$C$)$ of $300ppm.$ The data in the following table

were taken in the work area at the times indicated.

A worker on an $8$ hour shift is exposed to this toxic vapor. Assume that the worker is at lunch

between $12$:$00$ and $13$:$00$ and is not exposed to the chemical during that time.

Is the exposure of the worker to the toxic substance within compliance? If not, what are

the violations?

$TLV-$TWA$=\frac{\frac{?}{\text{b}\text{a}\text{r}}(C_1)T_1\frac{+}{b}ar(C_2)T_2+\text{c}\text{d}\text{o}\text{t}\text{s}\frac{+}{b}ar(C_n)T_n}{8hr}$

NOTE: Work your computations in a tabular form.