Tyrone Brown doesn't have an official title except the one stitched on his shirt, Maintenance.

His name is also on his shirt, and to the casual eye, he is on an equal footing with Joseph Howard, who does have an official title, Head Custodial Maintenance. 

Tyrone's actual job is as a floor sweeper, although he assists Joseph in anything that Joseph needs him for. They are often seen together around the complex.

Tyrone is known around the research facility as friendly, and people look forward to seeing him flash his white teeth when he smiles. Tyrone likes to smile a lot.

We first meet Tyrone in Book 2 of The Human-Hybrid Project, Inside the Darkness.