NASA Deputy Administrator Robert C. Seamans, Jr., said the cause of the accident had not yet been found. Corrective actions under study included choices of CM cabin and suit atmospheres, improved accessibility into and out of the CM cabin, and procedures to minimize the possibility of fires and to extinguish fires if they should occur.
Charges that the Apollo program was taking chances with lives in the effort to beat the U.S.S.R. to the moon were "completely unfounded; . . . before every one of our manned flights, as well as our ground test simulations, we have taken stock to be sure that there is nothing . . . undone or . . . done, that would in any way increase the risk to the astronauts." The astronauts had been party to decisions and part of the review process to make sure this was true. Associate Administrator for Manned Space Flight George E. Mueller emphasized that the Apollo program had been "paced at a deliberate pace"; it was the longest research and development program the U.S. had ever undertaken.
MSC Chief of Center Medical Programs Charles A. Berry testified that the cabin atmosphere used in the Apollo program - 100 percent oxygen at pressure of 3.5 newtons per square centimeter (5 pounds per square inch) - was based on extensive research over more than 10 years. The one-gas selection was based on tradeoffs among oxygen toxicity, hypoxia, spacecraft leakage, weight, and system reliability. And cabins had been purged with oxygen at some 10.3 newtons per square centimeter (15 pounds per square inch) during the prelaunch period for all manned launches since 1960 and all spacecraft vacuum chamber tests in Mercury, Gemini, and Apollo programs - primarily to prevent astronauts from getting the bends.
Three previous fires had occurred in the pure oxygen environment, but these had been in simulators and caused by test equipment and procedures that would not be used in spacecraft.
The three-door hatch, requiring 90 seconds to open, was used for the first time on CM 012, which had an inner pressure hull and an outer shell to carry the structural loads of reentry into the atmosphere on a return from the moon. Danger of a fast-opening escape hatch's accidentally opening in space - as the Mercury program's Liberty Bell hatch had opened after splashdown in July 1961 - had to be considered. Research on cabin accessibility, ongoing before the 204 accident, was now intensified.