Federal authorities investigating a deadly fireworks explosion on Oahu have started to slowly remove explosives that remain in the underground bunker where five workers were killed. 

Jordan Lowe, in charge of the Honolulu field office for the Bureau of Alcohol, Tobacco, Firearms and Explosives, said today three explosive specialists, three bomb technicians and a certified fire investigator have arrived from the mainland to work with Honolulu fire officials. 

Since Monday, they began to slowly and carefully remove the explosives, which will be burned somewhere else.

Lowe says that while the explosives are being removed, samples are being taken to help determine the cause of the blast.

What happened at the time of the blast can’t be determined until the explosives are removed from the site.