After a public bid, the plaintiff bought retrofitted spacers from the defendant manufacturer to improve the performance of its electrodialysis reversal system, which was designed to reduce the salinity of water taken from a lake. After the retrofit, the system experienced problems, causing water quality to decrease and, eventually, fires that forced the plaintiff to close its water plant down. On appeal, the court held that the district court erred in excluding evidence of similar fires at other facilities that used the same retrofitted system because Rule 404(b) applies only to “persons” and not to inanimate objects; the error, the court found, was not harmless because the authority could have used the other fires to rebut the defense that the plaintiff’s problems were caused by poor management. The district court also erred by barring evidence documenting the manufacturer’s attempts to improve the retrofitted product because contractual, not tort, issues were being litigated, and the remedial measures were relevant to causation rather than culpability. See Brazos River Authority v. GE Ionics, 469 F.3d 416 (5th Cir. 2006).