Should managers be ethical?

Consider a project with expected perpetual cash flows of $50,000 per year. The appropriate discount rate is 10%. The company has a choice of two machines to undertake this project. Machine A costs $400,000. With machine A, the project will leak some minor pollutant to a nearby river. The pollution amount is within legal limits. Alternatively, the company can use Machine B which costs $520,000 but completely seals the leak.

What should the company do? Undertake the project or not? With which machine?