A Texas A&M professor testifies in the case of Dennis Davis versus the Burlington Northern Santa Fe Railway Co.

Dr. Kirby Donnelly, was called to the stand Friday as an expert witness.

Donnelly told jurors about health risks associated with PAHs found in the solvents the railroad used.

In early 2008 Donnelly was also a part of a team of A&M researchers who conducted an independent study of Somerville schools. That's where they say they found toxins in the schools, comparable to the post 9-11 World Trade Center.

Dennis Davis claims while working at BNSF he was not protected from toxic chemicals produced by the plant.