Steve Blum

Laser Efficiency Kid (as Richard Cardona)

Richard Jenkins

Radiation Controls Officer

John Mahoney

Lt. Col. Conroy

John Lithgow

John Mathewson

Marshall Brickman

Director

Timothy Carhart

Relief Guard

Fred Melamed

Howard

Cynthia Nixon

Jenny Anderman

JD Cullum

Eccles (as John David Cullum)

Sully Boyar

Night Guard

Ned Eisenberg

C-4 Guy (uncredited)

Richard Council

Government Aide

Robert Sean Leonard

Max

Gregg Edelman

Science Teacher

Jill Eikenberry

Elizabeth Stephens

Adrian Sparks

Scientist

Christopher Collet

Paul Stephens

Abraham Unger

Roland (as Abe Unger)

Robert Schenkkan

Government Aide

Sarah Burke

Jenny's Parent

Warren Manzi

Day Attendant

Paul Austin

General

Curt Dempster

Scientist

Bran Ferren

Lab Assistant

David Quinn

Tennis

Thomas Baum

Writer