Speaking as one trained in emergency responses to Hazardous Materials releases, I know that a
typical household loaded into a 20' container would not be required to be placarded. The Federal DOT Emergency Response Guide is one of the references that we use, and
here is a link to that website. The Dept. of Transportation is the regulating body for containers on the highway and in ports and on ships, but, browsing around their website, they are not oriented towards serving a single family move to Hawaii. They are more oriented to dealing with commercial and industrial shippers of large quantities of hazardous materials, so it might drive you crazy trying to decipher their bureaucratic jargon.
If all you have are small quantities of household cleaners, paints, pesticides, bleach, and the like, and they are in their
original containers, you will not have any problems. Matson may have some special requirements (sounds like they don't if they referred you to a DOT phone line), but the regulating body is the Federal DOT.
Use common sense regarding transporting these materials. Example: if I have a $2.00 bottle of bleach, a quarter full, and I can't guarantee that my packing skills are such that I wouldn't worry about the container leaking or breaking open, is it worth risking the ruination of every stitch of clothing, bedding, and towels, etc. just to save fifty cents worth of bleach? For me, I'd give the bleach to a neighbor, and buy another bottle when I got to Hawaii. Likewise on other items. If you are not positive that the container will survive the trip, don't pack it. The warning about gasoline is a good one. Even if it doesn't find a source of ignition to burn your goodies, gasoline stinks. Likewise kerosene, Coleman lantern fluid, and pretty much all petroleum products.
Good luck.
Aloha! ;-)
], I'd think Matson would have it on their web site or something, rather than giving it a half asq answer[}
]. Good luck!