External Cost ■ Scenario Marginal External Cost(MEC)is the cost imposed on fishermen downstream for each level of production o Marginal Social Cost (MSC)is MC plus MEC Chapter 18 Slide 6Chapter 18 Slide 6 External Cost ◼ Scenario ⚫ Marginal External Cost (MEC) is the cost imposed on fishermen downstream for each level of production. ⚫ Marginal Social Cost (MSC) is MC plus MEC