From: How Big Was the Explosion That Devastated Beirut?
An explosion at a port in Beirut brought destruction to the Lebanese capital Tuesday, damaging buildings, killing more than 100 people, and injuring thousands of others. People recorded videos showing the blast wave and a towering red cloud that some compared to a nuclear weapon's mushroom cloud.
The exact cause of the blast is unclear, but the focus of an investigation is a warehouse improperly storing 2,750 tons of ammonium nitrate.
The blast registered as a magnitude 3.3 earthquake, and the effects of the explosion were felt miles away from the blast site. Experts told Insider the blast most likely had an explosive yield of several hundred tons of TNT equivalent.
—Nader Itayim | نادر ایتیّم (@ncitayim) August 4, 2020
Jeffrey Lewis, a nuclear and conventional weapons expert at the Middlebury Institute of International Studies in California, estimated the yield to be "between 200 and 500 tons, looking at blast damage, the shockwave, seismic signals, and the size of the crater."
—Emmanuelle Saliba 
(@_esaliba) August 5, 2020
That much explosive power is at least nearly twenty times greater than that of the GBU-43/B Massive Ordnance Air Blast (nicknamed the "Mother of All Bombs"), which has a blast yield of about 11 tons and is the most powerful non-nuclear weapon in the US arsenal.
The first known use of the weapon in combat was in April 2017 against the Islamic State in Afghanistan.
The explosion in Beirut was so powerful that some observers feared the city had experienced a nuclear detonation of some sort, a fear exacerbated by the mushroom cloud towering over the blast site after the explosion.
The governor of Beirut compared Tuesday's horrific explosion to the atomic bombs that devastated the Japanese cities Hiroshima and Nagasaki during World War II.
"In my life, I haven't seen destruction on this scale," he said.
A general view showing the damage at the site of Tuesday's blast.
Mohamed Azakir/Reuters
With an explosive yield of a few hundred tons, the Beirut blast would have been significantly less powerful than the atomic bomb that devastated Hiroshima, which had an estimated yield of about 15 kilotons.
The explosive power would, however, be comparable to the lowest-yield [B61 nuclear gravity bomb](Air Force Milestone for B61-12 Nuclear Gravity Bomb Tail Kit Assembly), which is believed to have an explosive yield of about 300 tons.
Some experts have estimated the explosive yield for what happened in Beirut to be [1 to 2 kilotons](Fireworks, ammonium nitrate likely fueled Beirut explosion | AP News), which would make the blast more powerful than some of the other small US tactical nukes.
"The comparison ends there," Hans Kristensen, a nuclear weaponry expert with the Federation of American Scientists who pointed Insider to unofficial blast-yield estimates of a few hundred tons, said of comparing the explosion in Beirut to a nuclear blast.
"The pressure wave would be much faster because the energy release from a uncontrolled nuclear chain reaction is much faster than the energy release from a chemical explosion," he said, further explaining that there would have also been intense radiation from a nuclear explosion, including the fallout from detonating a nuclear weapon on the ground.
Kingston Reif, a disarmament and threat reduction expert at the Arms Control Association, told Insider that while the explosive yield of the Beirut explosion might be comparable to that of some US nuclear weapons, "this does not at all mean that the explosion would have felt like the detonation of the lowest-yield B61 variant."
He argued that a "nuclear explosion would have been far worse, as it would include more extreme thermal and also radiation effects," adding that "nuclear weapons are not just another weapon for a reason."
