Let's consider a new scenario. of a custodian who works at the school. Calculate the asbestos cancer risk of a custodian who works 8 hrs per day for 250 days per year for 30 years at an air level of 0.01 f/ml.

Start with the risk of 1 death @ 0.0004 f/ml per lifetime exposure (i.e. 24/7 for 70 years) and work your way down. Assume everything is a linear response.

(show all work and calculations).