Why should improvements be made to the working conditions for low wage employees?

There are any number of reasons why there should be
improved working conditions for low wage employees.  One reason that comes to my mind is
that better working conditions create more productive employees, a benefit to
employers.  Another is that better working conditions lead to less employee turnover,
which is good for employers and employees.  A third reason is that better working
conditions tend to prevent unionization, which employers tend to think is a good thing. 
I should also add that in many instances, improved working conditions are a matter of
state and/or federal law, for example, laws that require a safe working environment for
most employees.  Additionally, in a country that says it values human rights and
decency, should not all employees have good working conditions, no matter what their
wage level?

As you work on your essay, no matter what
reasons you give to support your thesis, I want to offer you some advice.  First, it
will help you to keep your focus if you are able to define what you mean by "improved
working conditions."  This term could cover so many different areas, and I am not sure
you will want to leave it to your reader to decide what you mean when you use this
term.  Second, as you develop your ideas to support your thesis, work on using
examples.  If you want to show that productivity increases, explain what kinds of
improvements might allow this to happen.  You might do research on this, or you might
create hypothetical examples that rely on common sense or on your knowledge of various
work environments.  If you define your idea and use good examples, you will keep on
course much better and persuade your reader more effectively.