 The review board cited " many types and classes of combustible material " close to ignition sources . The NASA crew systems department had installed 34 square feet ( 3 @.@ 2 m2 ) of Velcro throughout the spacecraft , almost like carpeting . This Velcro was found to be flammable in a high @-@ pressure 100 % oxygen environment . Astronaut Buzz Aldrin states in his book Men From Earth that the flammable material had been removed per the crew 's August 19 complaints and Joseph Shea 's order , but was replaced before the August 26 delivery to Cape Kennedy . 
