It has been very widely reported that the character of H.E.R.B.I.E the robot was created because of concerns that The Human Torch might lead children to set themselves afire. Comics creator John Byrne did a story on the concept as writer/artist of the Fantastic Four comic book in the early 1980s, and Doug Wildey a frequent development artist and sometime producer for DFE claimed to have been part of the decision when interviewed for "Amazing Heroes" comics fan magazine. (Interestingly, as a longtime Hanna-Barbera contributor, he would have worked on Fantastic Four (1967), which DID feature The Torch). The actual catalyst for Herbie's creation was the simple fact that the TV rights to The Human Torch had already been optioned as part of the development deal between Marvel Comics, Universal Studios and CBS-TV, which resulted in prime-time, live-action versions of The Amazing Spider-Man (1977), The Incredible Hulk (1977), Captain America (1979) and Dr. Strange (1978). The character was just not legally available for use in these cartoons. A live-action Torch proved an unfeasible project given the limits of the budget and special effects technology of the day, and never reached production. One other character also optioned under that deal was The Sub-Mariner, abandoned because Man from Atlantis (1977) was felt to have been too similar.
Don Messick, Mike Road, Ted Cassidy, & Vic Perrin were the only voice actors who have previously done voice work for Fantastic Four (1967).
Rapper MF Doom has sampled audio from this cartoon for his songs, as Doctor Doom is the inspiration for his rapper persona.
The reason the Human Torch was trademarked separately from the Fantastic Four is that there was an earlier Golden Age hero of the same name, who used the Alias Jim Hammond. Marvel has had a trademarked on the name Human Torch since the early 1940s.
At 13 episodes this was the shortest Fantastic Four TV series ever made.