We write to report the results of cement testing that we have recently conducted and several conclusions we have reached based on that testing and documents subsequently provided to us by Halliburton. We wanted to report these results immediately to facilitate your consideration of their implications for offshore drilling safety...Taken together, these documents lead us to believe that: (1) Only one of the four tests...that Halliburton ran...for the final cement job at the Macondo well indicated that the slurry design would be stable; (2) Halliburton may not have had—and BP did not have—the results of that test before...April 19, meaning that the cement job may have been pumped without any lab results indicating that the foam cement slurry would be stable; (3) Halliburton and BP both had results...showing that a very similar foam slurry design to the one actually pumped at the Macondo well would be unstable, but neither acted upon that data...