Lebanon "The culprit" causing horrific explosion in the capital Beirut is ammonium nitrate, a compound commonly used as fertilizer, but can become a powerful explosive.

Lebanon's capital Beirut, on August 4, was rocked by a massive explosion that left at least 78 people dead and nearly 4,000 injured, and dozens of homes in the city destroyed or severely damaged.

Lebanese Prime Minister Hassan Diab said the disaster originated from 2,750 tons of ammonium nitrate stored for nearly 6 years in a warehouse near the city's harbor.

The amount of ammonium nitrate on the ship has been stored in a warehouse in Beirut port for the past 6 years without taking the necessary safety measures.

Ammonium nitrate is commonly used as a fertilizer, but can become a highly explosive if impurities or mixed with flammable fuels.

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Ammonium nitrate has the chemical formula NH4NO3.

Under normal conditions, ammonium nitrate is very stable and difficult to detonate.

A security source told Reuters that the ammonium nitrate explosion occurred when workers welded a hole in the warehouse, likely causing fires and detonations.

Ammonium nitrate will begin to decompose when heated to temperatures above 76 degrees Celsius. However, when heated rapidly or ignited, this compound reacts and produces nitrogen, oxygen and steam.

"The actual explosion is the process of switching from high energy to low energy of a compound in a short time. The energy released is the power of the explosion," said Ian Rae, a professor at the University of Melbourne.

He added that the process also requires increased pressure in enclosed spaces, unable to spread around.

The shockwave immediately appeared after the fireball erupted from the explosion.

The explosive potential causes many countries to impose strict regulations on ammonium nitrate storage and handling.

The US government also set a series of regulations on the production, storage and use of ammonium nitrate.

Ammonium nitrate has caused many fatal problems in the past.

The worst industrial disaster in American history was also related to ammonium nitrate.