Throughout the 1980's and 1990's, American copyright lengths were extended, and looser requirements for a work to gain a copyright were implemented. This has resulted in few video games entering the public domain without being intentionally released by the copyright holder. The only notable exceptions to this are training and propaganda video games developed or commissioned by the United States federal government; while they are allowed to own trademarks, they legally cannot own copyrights. This exception applies to games such as Recycle City, an educational game website hosted by the Environmental Protection Agency, and the America's Army series, which was devised as a recruitment tool by Colonel Casey Wardynski and initially published by the U.S. Army.