Massive explosion in Beirut

The catastrophic explosion at Beirut port on August 4 was caused by over 2,700 tonnes of ammonium nitrate kept in storage for over six years.
In its pure form, ammonium nitrate (NH4NO3) is a white, crystalline chemical which is soluble in water.
It is the main ingredient in the manufacture of commercial explosives used in mining and construction.
It is a common chemical ingredient of agricultural fertilisers.
It is also the main component of the explosive composition known as ANFO — ammonium nitrate fuel oil.
In India, its usage is regulated as per The Ammonium Nitrate Rules, 2012, under The Explosives Act, 1884.
The rules also make storage of ammonium nitrate in large quantities in populated areas illegal in India.
An ammonium nitrate explosion produces massive amounts of nitrogen oxides. Nitrogen dioxide (NO?) is a red, bad-smelling gas.
It can irritate the respiratory system. Elevated levels of these pollutants are particularly concerning for people with respiratory conditions.