Bill Marinelli is the President and Chief Executive Officer of Physical Sciences Inc. (PSI).  He received an Sc.B. in Chemistry from Brown University in 1977 and a Ph.D. in Physical Chemistry from the University of California, Berkeley in 1981.  He subsequently took a postdoctoral position at Cornell University where he worked on the development of chemical lasers.

In 1983 he joined the technical staff of PSI, headquartered in Andover, MA.  The company is employee-owned, has ~300 members of the technical and administrative staff and has >$90M in annual revenues, including significant participation in the Small Business Innovation Research Program.  It provides advanced R&D and production capability to the departments of Defense, Energy, and Homeland Security as well as NASA, NIH, and a broad range of commercial customers.  During his tenure at PSI he has assumed a series of positions of increasing technical and operational management responsibility while maintaining a personal technical focus on fixed site, mobile, and airborne detection technologies for chemical and biological defense.