Negative Labor Income

I am not sure if this is a software issue or analysis question - but - I ran the impact of a construciton project in Fulton County GA and was reviewing the impacts by sector and noticed the induced and indirect labor income impacts for Sector 25 Mining and Quarrying Stone.. were negative. How can a compensation impact be negative? Its small - less than $60 for indirect and less than $10 for induced - but am not sure how an impact can be negative. Is this a software issue?