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. As presented in the video, 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