I wouldn't know about that, maybe it varies from state to state?
I just found this:
http://209.85.173.104/search?q=cach...ml+laws+burial+idaho&hl=en&ct=clnk&cd=1&gl=us
snip
Embalming: No state requires routine embalming of all bodies. Special circumstances-such as an extended time death and disposition- may make it necessary under state law. Interstate transportation by a common carrier may also necessitate embalming, although most airlines will waive that requirement if there are religious objections. Refrigeration or dry ice can take the place of embalming in many instances. In some states, embalming may be required by law if the person has died of a communicable disease, although this is a seriously flawed requirement.