Why is Saint James a patron of laborers?

While I do not know the actual reason for James being made the patron of laborers, I can surmise that the following passage from the Epistle of St. James may have influenced the decision:

"You have faith and I have works. Show me your faith apart from your works, and I by my works will show you my faith."

There is a debate as to whether James actually wrote the Epistle or if it was written by someone else on his behalf. However, it is attributed to St. James and the writing is considered as canonical.