John Lithgow

John Mathewson

Christopher Collet

Paul Stephens

Cynthia Nixon

Jenny Anderman

Jill Eikenberry

Elizabeth Stephens

John Mahoney

Lt. Col. Conroy

Richard Jenkins

Radiation Controls Officer

Sully Boyar

Night Guard

Timothy Carhart

Relief Guard

Gregg Edelman

Science Teacher

JD Cullum

Eccles (as John David Cullum)

Abraham Unger

Roland (as Abe Unger)

Robert Sean Leonard

Max

Fred Melamed

Howard

Ned Eisenberg

C-4 Guy (uncredited)

Richard Council

Government Aide

Robert Schenkkan

Government Aide

Steve Blum

Laser Efficiency Kid (as Richard Cardona)

Sarah Burke

Jenny's Parent

Warren Manzi

Day Attendant

Paul Austin

General

Adrian Sparks

Scientist

Curt Dempster

Scientist

Bran Ferren

Lab Assistant

David Quinn

Tennis

Geoffrey Nauffts

Craig

Katherine Hiler

Emma

Trey Cummins

Terry

Steve Borton

Local FBI

Harlan Cary Poe

Local FBI

Ned Schmidtke

Jenny's Parent

Allen DeCheser

Jenny's Brother

Artie DeCheser

Jenny's Brother

Fred G. Smith

Conroy's Lieutenant

Manny Jacobs

Moore

Charles Fields

Price (as Charlie Fields)

Eric Hsiao

Saito

Heather Rose Dominic

Flirting Kid

Bruce Smolanoff

Flirting Kid

John Doumanian

Cabbie

Tom Tarpey

Injection Doctor

Roger Caine

FBI (as Alec Massey)

Edward D. Murphy

FBI

Joan Harris

Barbara Collins - TV Reporter

Ken Chapin

Command

Peter McRobbie

Electronics

Warren Keith

Computer

Bruce Jarchow

Interrogator

Stephen Markle

Interrogator

Al Cerullo

Helicopter Pilot

Michael Telesco

Day Security Receptionist

Richard Caselnova

SWAT

Frank Ferrara Sr.

SWAT

Jimmie Ray Weeks

SWAT

Dan Butler

SWAT

Steve Zettler

SWAT

Debbie Gibson

Background (uncredited)