The accident at the Three Mile Island nuclear power plant resulted from a communication failure. Following an incident at an Ohio plant a year and a half earlier, B. M. Dunn, manager of Emergency Core Cooling Systems Analysis at Babcock and Wilcox (engineers), wrote a memorandum making specific recommendations on written instructions for nuclear plant operating procedures. F. Walters, a member of the Plant Performance Services staff, still had concerns about the recommendations and did not forward them to the utilities concerned. While Walters investigated these concerns, the accident at Three Mile Island occurred. Shortly thereafter, the Operating Plant Services division of Babcock and Wilcox issued "supplementary operating instructions" to the utilities, which were almost identical to Dunn's recommendations. Although both the content of the memo and Dunn's managerial rank should have ensured compliance with the memo, the primary communication context set up by Dunn was inconsistent with the actual decision making process for his recommendations. The memo was sent to the wrong audience and was written in such a way as to preclude action. To a significant extent, the lack of effective response to his memorandum can be traced to his misinterpretation of the audiences for the memorandum. The resulting accident suggests that, no matter how good the engineering, it is not finished until organizations make decisions and take action. This requires effective communication. (HTH)