[6][7][8] To date, the Halabja massacre remains the largest chemical weapons attack directed against a civilian-populated region in human history,[9] killing between 3,200 and 5,000 people and injuring 7,000 to 10,000 more.

[10][1][11] Preliminary results from surveys of the affected areas showed increased rates of cancer and birth defects in the years since the attack took place.

[16] Al-Majid, who was captured during the 2003 invasion of Iraq, was put on trial and found guilty of ordering the attack; he was sentenced to death in June 2007 and executed by hanging in January 2010.

From 1985, the Iraqi Ba'athist government under Saddam Hussein decided to eradicate pockets of Kurdish insurgents in the north and strike down the peshmerga rebels by all means possible, including large-scale punishment of civilians and the use of chemical weapons.

The Halabja event was also part of Iraqi efforts to counter-attack Kurdish and Iranian forces in the final stages of Operation Zafar 7.

[19]Survivors said the gas at first smelled of sweet apples[20] and reported that people "died in a number of ways, suggesting a combination of toxic chemicals.

"[21] Citing an interview with a university student who survived the attack, the international NGO, Human Rights Watch, reported that "some [victims] 'just dropped dead'.

[22] "Those who were in the thick of the 'death cloud' died in suspended animation" according to Dlawer Ala'Aldeen of Nottingham University, who collected detailed data between 1987 and 1988, including numbers, places and types of chemical weapon attacks across Iraqi Kurdistan.

The United States (U.S.) government and its intelligence agencies suggested that Kurdish civilians had not been deliberately targeted, and attempted to place responsibility for the attack on Iran.

Punitive measures such as unilateral sanctions would not be effective in changing Iraq's behaviour over chemical weapons, and would damage British interests to no avail.

[34] Joost Hiltermann states that Iraq took the U.S. "disinformation" about Halabja as "another green light ... to gather up and methodically kill tens of thousands of Kurds" over the course of the ensuing Anfal campaign, which continued until September 1988.

In Hiltermann's analysis, the Anfal campaign "surely was not a US policy objective; nevertheless, it resulted directly from failing to call the Iraqis to a halt [after Halabja].

"[35] In response to further Iraqi chemical attacks on Kurdish civilians after the August 1988 ceasefire with Iran, U.S. senators Claiborne Pell and Jesse Helms called for comprehensive economic sanctions against Iraq, including an oil embargo and severe limitations on the export of dual-use technology.

"[37] A 20 March 1988 Iraqi memorandum "placed the casualty figures 'as a result of the chemical attack' as 900–1,000 'killed and a large number wounded' near Halabjah and some 2,500 in the city itself.

[45] In the meanwhile, an Iraqi high-ranking authority officially confessed in a meeting with Javier Pérez de Cuéllar, the Secretary-General of the United Nations for the utilization of chemical weapons by Iraq.

Additionally, "other cancers, respiratory ailments, skin and eye problems, fertility and reproductive disorders are measurably higher in Halabja and other areas caught in chemical attacks.

[48] Among several documents revealed during the trial of Saddam Hussein, one was a 1987 memo from Iraq's military intelligence seeking permission from the president's office to use mustard gas and the nerve agents sarin and tabun against Kurds.

A second document said in reply that Saddam had ordered military intelligence to study the possibility of a "sudden strike" using such weapons against Iranian and Kurdish forces.

Singapore-based firm Kim Al-Khaleej, affiliated to the United Arab Emirates, supplied more than 4,500 tons of VX, sarin and mustard gas precursors and production equipment to Iraq.

[54] Dieter Backfisch, managing director of West German company Karl Kolb GmbH, was quoted by saying in 1989 that "for people in Germany poison gas is something quite terrible, but this does not worry customers abroad.

The court ruled that the chemical attack on Halabja constituted genocide, but van Anraat was found guilty only of complicity in war crimes.

[5] Joost Hiltermann, who was the principal researcher for Human Rights Watch between 1992 and 1994, conducted a two-year study of the massacre, including a field investigation in northern Iraq.

[62] In 2001, Jean Pascal Zanders of the Stockholm International Peace Research Institute (SIPRI)'s Chemical and Biological Warfare Project also dismissed the allegations, arguing that "The coloring of the victims is more suggestive of sarin, which was in Iraq's arsenal.

Prior to Halabja, Iranian forces made widespread use of amyl nitrite to counter what they repeatedly alleged was Iraqi cyanide gas.

"[65] According to Hiltermann, the literature on the Iran–Iraq war reflects a number of allegations of chemical weapons use by Iran, but these are "marred by a lack of specificity as to time and place, and the failure to provide any sort of evidence."

Hiltermann called these allegations "mere assertions" and added that "no persuasive evidence of the claim that Iran was the primary culprit was ever presented.

"[66] In fact, far from having a meaningful chemical warfare capability, Iran's effectiveness merely in protecting its own soldiers from chemical attacks is open to question as the low-quality protective equipment that it belatedly received from East Germany and North Korea was intended for use against paint fumes; the unwillingness of many Iranians to shave their beards also limited the efficacy of the masks.

An intelligence report [dated 27 June 1988] discussing North Korea's help to the Iranians to develop an indigenous mustard gas capability, however, pointed toward a future where Iraqi troops might need to worry about chemical attacks.

On 16 March 2006, a few thousand residents, many of them students in high school or university, demonstrated at the site in protest of what they perceived as the neglect of living Halabjans and the Kurdish leadership's commodification of the tragedy.

The memorial was set on fire, destroying most of its archives; student protestor Kurda Ahmed was shot dead by the police and dozens of people were injured.