On August 4, 2020, a fire at the docks of Beirut, Lebanon ignited some 2,700 tons of ammonium nitrate, a common compound used for fertilizer and explosives.

During a following press conference, Trump claimed that the explosion “looked like a terrible attack.” When asked to elaborate, Trump remarked,

Well, it would seem like it based on the explosion. I’ve met with some of our great generals and they just seem to feel that it was. This was not some kind of a manufacturing explosion type of event. This was seems to be, according to them, they would know better than I would, but they seem to think it was a attack. It was a bomb of some kind. Yes.

Department of Defense officials rejected Trump’s claim, saying instead that there was yet no indication of any kind of attack.

Ammonium nitrate disasters have happened several times throughout history. The largest non-nuclear bomb in the American arsenal, the MoAB (Mother of All Bombs) has a yield of 11 tons of TNT. The catastrophic explosion in Beirut was equivalent to approximately 1 kiloton of TNT.

Sky News – Beirut explosion: At least 100 dead and 4,000 injured after ‘ammonium nitrate blast’ 
CNN – US defense officials contradict Trump: No indication yet of attack in Beirut
The Independent – ‘It was a bomb’: Trump says deadly Beirut explosion was ‘terrible attack’ – despite no evidence it was deliberate
Wikipedia – Ammonium nitrate disasters
Wikipedia – GBU-43/B MOAB
Wikipedia – 2015 Tianjin explosions (ammonium nitrate explosion used to determine approximate yield by comparison)
Wikipedia – Largest artificial non-nuclear explosions, Rank order of largest conventional explosions/detonations by magnitude