The Hawaii National Guard is holding the largest disaster preparedness exercise in its history with more than 2,200 participants from multiple states responding to a simulated hurricane and other events across Oahu, Hawaii island, Maui and Kauai.

Some Chinook and Black Hawk helicopter activity will be seen, Waimanalo will request assistance — possibly for debris clearance — a mass-casualty exercise will take place at the Queen’s Medical Center-West Oahu, and harbor chemical spills will be dealt with in Honolulu and on Hawaii island, officials said.

“It combines the civilian government and military organizations, and that’s important because we need to get the organizations working together — understanding each other’s capabilities — before we get to a natural disaster, a real natural disaster event,” said Brig Gen. Bruce Oliveira, the head of the Hawaii Army National Guard.

The Hawaii Guard is hosting exercise Vigilant Guard/Makani Pahili 2015, which started Monday and will run for just over a week. More than 700 of the participants are from Utah, Nevada, California, Oregon and Guam. Observers from seven Asia-Pacific countries also are attending.

Makani Pahili is the state’s annual hurricane exercise led by the Hawaii Emergency Management Agency, formerly known as state Civil Defense, which coincides with the beginning of the annual hurricane season.

Vigilant Guard is a large-scale, regional exercise sponsored by U.S. Northern Command and the National Guard Bureau. This year, the two exercises have been combined to create one big disaster preparedness drill, the Hawaii National Guard said.

Some of the scenarios that will be exercised by military personnel and first responders include a disease outbreak, cyberattack, chemical spill, search and rescue, a collapsed structure, medical mass casualty and more.

On Hawaii island, training will occur at the Keaukaha Military Reservation. On Maui, the Army National Guard’s Puunene Armory and the Maui Fire Department training area will be used. On Kauai, exercises will occur at Vidinha Stadium and the National Guard’s Hanapepe armory.

“If you were to have a natural disaster in the continental United States, you could have support from other forces and other organizations just driving across the border to assist,” Oliveira said. “Here in Hawaii, we depend primarily and initially with what we have here, and then it will take a couple of days before we actually see other forces coming in.”

Hawaii has agreements with West Coast states for support, Oliveira said.

An alternate port scenario at Joint Base Pearl Harbor-Hickam will be tested Friday, and the mass-casualty drill with role players portraying the injured will be held outside the Queen’s Medical Center-West Oahu Saturday morning. A “rubble pile” search and rescue and extraction exercise at Kalaeloa also will be held Saturday.

Hawaii Army National Guard Col. Moses Kaoiwi said in a disaster as big as the hurricane envisioned for the exercise, the governor can submit a request for a “dual status” commander who can oversee both National Guard and active-duty troops.

At the Hawaii National Guard offices across from Diamond Head, a makeshift hurricane headquarters swarmed Wednesday with command troops working on laptop computers. The 25th Infantry Division at Schofield Barracks and U.S. Army Corps of Engineers had representation at the center.

The National Guard can provide damage assessment, debris clearance, security and other functions in an emergency.

“So really what happens is, this entity really creates unity of effort in planning and responding to a disaster so that it’s seamless and quick,” Kaoiwi said.