If Tuesday's massive explosion in Beirut was an accident -- as authorities claim --- "it was an accident waiting to happen," former Trump national security spokesman Michael Anton told "Bill Hemmer Reports" Wednesday.

Anton told guest host John Roberts the substance which ignited to cause the powerful blast was ammonium nitrate -- a key component of agricultural fertilizer that had been stored in a warehouse at Beirut's port since 2013, when it was offloaded from a Russian-leased ship that had made an unscheduled stop there.

HEARTSTOPPING VIDEO SHOWS LEBANESE BRIDE POSING FOR EXPLOSION MOMENTS BEFORE BLAST

"Officials have worried about this for years saying we have to get this out of here," Anton said. "This dragged on for seven years."

Anton added that Lebanon's government has been in a state of turmoil for more than four decades and is neither completely functional, nor does it have full control of all of its territory.

"I think the government itself will have a hard time getting a handle on this and American intelligence will be looking at it too," he said. "Any time something happens in Lebanon ... this country has been wracked by terrorism, civil war and economic deprivation for decades. Out of such difficult situations, it’s hard to find the truth."

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Roberts noted that U.S. officials have told Fox News they have no evidence to support President Trump's claim Tuesday that the Lebanese explosion was the result of a bomb. Anton said that, unlike some other combustible substances, ammonium nitrate does need more effort than a simple match to ignite.

According to Lebanon's Health Ministry, Tuesday's blast killed 135 people and injured approximately 5,000 others.