For the first time in military history, a civilian population is targeted for chemical attack when Iraqi warplanes bombed the Iranian town of Sardasht.

Mustard gas or sulfur mustard are names commonly used for the organosulfur chemical compound bis(2-chloroethyl) sulfide, which has the chemical structure S(CH₂CH₂Cl)₂, as well as other species. In the wider sense, compounds with the substituents −SCH₂CH₂X or −N(CH₂CH₂X)₂ are known as sulfur mustards or nitrogen mustards, respectively, where X = Cl or Br. Such compounds are potent alkylating agents, making mustard gas acutely and severely toxic. Mustard gas is a carcinogen. There is no preventative agent against mustard gas, with protection depending entirely on skin and airways protection, and no antidote exists for mustard poisoning.

On 28 June 1987, Iraq dropped mustard gas bombs on Sardasht, West Azerbaijan, Iran. In two separate bombing runs on four residential areas, the attack killed 130 people and injured 8,000. The gas attacks occurred during the Iran–Iraq War when Iraq frequently used chemical weapons against Iranian civilians and soldiers.

Sardasht is a city in the Central District of Sardasht County, West Azerbaijan province, Iran, serving as capital of both the county and the district.