John Lithgow

Character: John Mathewson

Christopher Collet

Character: Paul Stephens

Cynthia Nixon

Character: Jenny Anderman

Jill Eikenberry

Character: Elizabeth Stephens

John Mahoney

Character: Lt. Col. Conroy

Richard Jenkins

Character: Radiation Controls Officer

Sully Boyar

Character: Night Guard

Timothy Carhart

Character: Relief Guard

Gregg Edelman

Character: Science Teacher

JD Cullum

Character: Eccles (as John David Cullum)

Abraham Unger

Character: Roland (as Abe Unger)

Robert Sean Leonard

Character: Max

Fred Melamed

Character: Howard

Ned Eisenberg

Character: C-4 Guy (uncredited)

Richard Council

Character: Government Aide

Robert Schenkkan

Character: Government Aide

Steve Blum

Character: Laser Efficiency Kid (as Richard Cardona)

Sarah Burke

Character: Jenny's Parent

Warren Manzi

Character: Day Attendant

Paul Austin

Character: General

Adrian Sparks

Character: Scientist

Curt Dempster

Character: Scientist

Bran Ferren

Character: Lab Assistant

David Quinn

Character: Tennis

Geoffrey Nauffts

Character: Craig

Katherine Hiler

Character: Emma

Trey Cummins

Character: Terry

Steve Borton

Character: Local FBI

Harlan Cary Poe

Character: Local FBI

Ned Schmidtke

Character: Jenny's Parent

Allen DeCheser

Character: Jenny's Brother

Artie DeCheser

Character: Jenny's Brother

Fred G. Smith

Character: Conroy's Lieutenant

Manny Jacobs

Character: Moore

Charles Fields

Character: Price (as Charlie Fields)

Eric Hsiao

Character: Saito

Heather Rose Dominic

Character: Flirting Kid

Bruce Smolanoff

Character: Flirting Kid

John Doumanian

Character: Cabbie

Tom Tarpey

Character: Injection Doctor

Roger Caine

Character: FBI (as Alec Massey)

Edward D. Murphy

Character: FBI

Joan Harris

Character: Barbara Collins - TV Reporter

Ken Chapin

Character: Command

Peter McRobbie

Character: Electronics

Warren Keith

Character: Computer

Bruce Jarchow

Character: Interrogator

Stephen Markle

Character: Interrogator

Al Cerullo

Character: Helicopter Pilot

Michael Telesco

Character: Day Security Receptionist

Richard Caselnova

Character: SWAT

Frank Ferrara Sr.

Character: SWAT

Jimmie Ray Weeks

Character: SWAT

Dan Butler

Character: SWAT

Steve Zettler

Character: SWAT

Debbie Gibson

Character: Background (uncredited)