you have to apply with the BATFE
Yes, you need a license from the BATF to legally use high explosives. Please go to the link below to read further on what is required to acquire an explosives license.
In the US, you apply for a business license and apply to the Bureau of Alcohol, Tobacco, Firearms and Explosives for an 01 Federal Firearms License (Dealer's license).
It is illegal to manufacture fireworks without a license because they are Class B explosives.
No. Not without a license.
The Bureau of Alcohol, Tobacco, Firearms and Explosives web site has the information that you are looking for.
base weapons safety
Primary high explosives
The three categories of high explosives are primary explosives, secondary explosives, and tertiary explosives. Primary explosives are very sensitive and are used to initiate a detonation. Secondary explosives are more stable and are commonly used in commercial and military applications. Tertiary explosives are less sensitive and are often used as propellants.
It is still possible to use dynamite. However, you would need a BATFE explosive license due to laws. This would require you show a legitimate need for explosives.
explosives
You have to go to an explosives dealer that sells TNT. Yes, they exist. They will ask to see your explosives license before you can buy anything from them--like any business that deals strictly with "the trade," if you're not in the trade they won't even let you buy a Coke out of the vending machine in the office.
The three categories of explosives are: high explosives, including dynamite and TNT, which detonate with a supersonic shockwave; low explosives, such as black powder and gunpowder, which deflagrate with a subsonic burn rate; and secondary explosives, like RDX and PETN, which are more powerful and sensitive than primary explosives like TNT.