Are "Homemade" Fireworks LEGAL in the U.S.?

[FinnAmerican]

Found this information on Keystone Fireworks [Pennsylvania] website, pertaining to "Homemade" Fireworks:
http://www.pyrotalk.com/bulletin/attachment.php?attachmentid=6086&stc=1

[FinnAmerican]

"Fireworks made from mail order kits are illegal and dangerous." [American Pyrotechnics Association]

[leftiluci]

False information. As a member of more than a couple clubs, it's perfectly legal to construct your own, as long as it is fired on the same property, and hasn't traveled once completed. If the project takes multiple days to complete, then legally it should be stored in a magazine, just for manufacturing.

[RalphieJ]

If I were the owner or officer of a fireworks company, I'd say the same whether true or not.