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Using the information on the www.osha.gov website,answer the following questions

ID: 98551 • Letter: U

Question

Using the information on the www.osha.gov website,answer the following questions,showing all work where appropiate

1) the following exposures to airborne acetone were experienced by the same worker during her single workday

a) search for and determine the OSHA- 8hr PEL in ppm (www.osha.gov)

b) determine if this worker was overexposed by calculating the 8-hr TWA

9:00 - 10:00 10:00 -11:30 11:30 -12:00 12:00 -2:00 2:00 - 5:00   

1400 ppm 600 ppm 100 ppm 1500 ppm 1000 ppm   

2) During an 8-hour day,workers in one plant are exposed to a mixture of 3 chemical vapors considered to have additive effects.calculate the overall dose and determine if the OSHA standard is violated for the mixture?

vinyl toluene - 41 ppm (PEL = 100ppm)

propane - 170 ppm ( PEL = 1000 ppm)

Tri ethyl amine - 9 ppm (PEL = 25ppm)

Explanation / Answer

1) a) The Occupational safety and health administration (OSHA) has set maximum permissible exposure limit (PEL) for acetone to be 1000 ppm (parts per million).

b) From 9 to 10 - 1400 ppm

From 10-11.30 - 600 ppm. So, 10 to 11 is 400 ppm

11.30 to 12 is 100 ppm. So, from 11 to 12 is 300 ppm

12 to 2 is 1500 ppm. So, 12 to 1 is 750 ppm and 1 to 2 is 750 ppm.

2 to 5 is 1000 ppm. So, 2-3 is 333.33 ppm; 3-4 is 333.33 ppm; 4-5 is 333.33 ppm.

The 8 hour time weighted average (TWA) is,

= (1400+400+300+750+750+333.33+333.33+333.33)/8

= 4600/8

= 575 ppm

The worker is not over exposed.