1946, the series delivered a powerful blow against the Ku Klux Klan's prospects in the northern US. Stetson Kennedy, a human rights activist, infiltrated the KKK and other racist/terrorist groups. Concerned that the organization had links to the government and police forces, Kennedy decided to use its findings to strike at the Klan in a different way. He contacted the Superman producers and proposed a story where the superhero battles the Klan. Looking for new villains, the producers eagerly agreed. Kennedy provided information—including details of Klan rituals and the like to the writers. The result was a series of episodes, "Clan of the Fiery Cross", in which Superman took on the Klan. The trivialization of the Klan's rituals and natures had a negative impact on Klan recruiting and membership numbers. Reportedly, Klan leaders denounced the show and called for a boycott of Kellogg's products. However, the story arc earned spectacular ratings, making Superman the most highly rated kids' radio program, and the food company stood by its support of the show. Superman historian Michael Hayde has cast doubt on whether actual KKK codewords and details were broadcast in the Clan of the Fiery Cross story arc. He wrote, "[O]ne is hard pressed to uncover anything that might be construed as proprietary to the KKK, with the exception of one – and only one – sequence, heard in episode #2". The story-arc was loosely adapted for a DC Comics limited series, Superman Smashes the Klan by Gene Luen Yang, and was released in October 2019. Stories The syndicated series, titled simply Superman, first aired via pre-recorded transcription disks over 11 stations beginning on February 12, 1940, with an origin story, "The Baby from Krypton". The series aired in 15-minute episodes three times a week until May 9, 1941, with the conclusion of the "Nitrate Shipment" storyline. By that time, it had expanded to 63 stations. The first 19 episodes had individual titles that told three overall stories: The series then moved to multi-part cliffhanger stories, beginning with "The Mystery of Dyerville". Some stories spanned just a few episodes; others, like "The Last of the Clipper Ships", went on for up to 20 parts. "The Mystery of Dyerville" (March 1940) (2 parts, actually concludes the story begun on March 18) "The Emerald of the Incas" (April 1940) (6 parts) "Donelli's Protection Racket" (April 1940) (6 parts) "Airplane Disasters at Bridger Field" (April–May