A worker in a wastewater treatment plant found a hole in a tank containing chlorine gas. This has caused 20 kg/s of chlorine gas to be released 50 m off the ground.

(1) Estimate the concentration of the release 500 m downwind on the ground. Assume that the release occurs in the daytime during strong sunlight with a wind speed of 5.5 m/s.

(2) Determine the percentage of fatalities if all workers in the plant are exposed for 1 hour. The molecular weight of chlorine gas is 70.91 g/mol.