A. risk may be described in terms of likelihood and consequence. using these terms, compare the risk of living downwind of a coal-fired power plant and living closely downriver from hydroelectric power plant. (4 points)
b. a 70 kg man breathes 20 m3 of air each day containing 170 ppb of the carcinogen trichloroethylene (mw = 131.4 g/mol). the inhalation unit riskfactor is 4. ixi 0-6 (ug/m3 ) l . is this a safe exposure? (5 points)
c. arsenic is a chemical that causes cancer, and also other toxic effects. it has a reference dose of 3x10-4 mg/kg-d and an oral slope factor of 1.5 (mg/kg-d) i
calculate the lifetime cancer risk and the hazard quotient for a 50 kg woman
consuming 2 l/d of water containing 6 ppb of arsenic in a residential exposure (350 days/year for 30 years). are either of these exposures considered unsafe? (8 points)
d. read the following report from the ontario ministry of labour. describe at least three ways that this tragedy could have been prevented, considering control at the source, control along the path, and control at the worker. state which of the three is preferred, and why. (8 points)
paper milt fined $150,000 after worker burned in dust explosion at idled plant january 29, 2016
fort frances, on - resolute fp canada inc., operator of a paper mill, pleaded guilty and has been fined $150,000 after a worker was burned following an explosion of wood dust.
the paper mill, located at mowatt avenue and sinclair street in fort frances, was idled in 2014 but its bio mass boiler was still in operation to provide heat for the mill through the winter months. it was expected that the boiler would be idled after the winter when heating was no longer required.
the boiler was capable of running on either natural gas or bio mass. in 2008 an engineering assessment of the conveyor system for the boiler concluded that the system did not present a dust explosion hazard, owing to the particle size and moisture content of the fuel being used as bio mass.
in the days before the incident, workers had been doing a cleanup of the plant in anticipation of its closure. up to 15 wheelbarrow loads of fine, dry wood dust that had been swept up from around the plant were dumped into the conveyor system. at that time, the boiler was running on natural gas.
on february 27, 2014, it was resolute's intention to switch the boiler over to bio mass to burn off remaining fuel stock. on that day, a maintenance worker was checking on a plug-up of material in one of the conveyors and was near the operating controls at the head of the conveyor. the worker had cleared the plug-up and was looking into the conveyor to check whether it was going to plug up again.
as the dry wood dust that had been dumped into the conveyor was travelling on the conveyor, it was ignited by an undetermined source and a dust explosion occurred. a fireball traveled through the conveyor and out the end where the worker was standing. the worker received burns to the body.
because the boiler system had not been designed to burn only fine, dry wood dust, but rather fuel with a certain moisture content and particle size, the protective measures of section 63 of the regulation for industrial establishments dealing with explosive hazards were not in place.