Monsanto procured U.S. Patent No. No. 3,382,280, issued May 7, 1968, having the title 3',4'-dichloropropionanilide (known as 3,4-DCPA or propanil), a herbicide that selectively killed weeds without killing crop plants such as rice.[1] In November 1969 Monsanto sued Rohm and Haas for patent infringement. The only substantial issue was the validity of the patent, and that ultimately turned on whether Monsanto had committed fraud on the Patent Office in procuring the patent.[2]