Baroness Emma Nicholson was this week the first foreigner to testify in the Baghdad trial of 42 Iraqis, including Saddam's hatchet-man "Chemical Ali" Hassan al-Majid, over the brutal crackdown that followed a Shiite uprising after the 1991 Gulf War.
The mass expulsion of locals and the draining of around 90 percent of the marshes in the country's south, which sent around 50,000 refugees into Iran, is considered by the United Nations to be one of the worst environmental disasters in history.
Nicholson told AFP late Thursday after testifying in the tightly guarded trial in the Iraqi capital that she saw first-hand the destruction of the region, including through the alleged use of chemical weapons, on a series of around 75 visits to Iraq and neighbouring Iran during the 1990s.
"The people were farmers and fishermen whose farms and fishing grounds were being destroyed," said Nicholson, head of the AMAR charity which provides assistance to Iraqi refugees and internally displaced people, including the Marsh Arabs.
"Their villages, their towns, their cities were being bombed, being shelled, being burnt, and over the next few years the Marsh Arabs were forcibly displaced," she said.
"After 1995 there was no point going in to the marshes because they were completely drained.
"I'd certainly use the word genocide (in describing the campaign) against the Marsh Arab people."
The trial, which began in June and is expected to reach a verdict by the end of the year, is the latest in a string of cases to come to trial in Iraq since the overthrow of Saddam in a 2003 US-led invasion.
The draining of the marshes, considered by some to be the location of the Biblical Garden of Eden, was carried out by Saddam in a bid to flush out Shiite rebels hiding out in the sprawling network of waterways.
Footage of the trial on state-run television showed Nicholson speaking through a translator and displaying pictures of the victims of the crackdown, as "Chemical Ali" Majid and others sat in the dock.
Nicholson told AFP she witnessed the result of apparent chemical weapons use by Iraqi forces, with medical workers under her direction treating "people coughing their insides out."
"Some of the chemical weapons turned people blue and they'd blown up and died.
"Others were clearly mustard gas because (the victims) talked about yellow bombs coming from the sky and no one could breathe, they were burning all over."
Nicholson however said she had no evidence of individual complicity by any member of Saddam's regime on trial before the tribunal.
"Indeed I would have wanted at the time to find people who were responsible but it was not within my capacity to do so. I would have very much wanted indeed to face them," she said.
The trial is not the first time senior Iraqi officials have been accused of using chemical weapons to crush resistance.
Majid was first sentenced to death in June 2007 for ordering the gassing of tens of thousands of Kurds in the 1998 Anfal campaign, which earned him his grim moniker.
He has received two other death sentences for crimes including war crimes and crimes against humanity during the brutal 1991 crackdown on the Shiite uprising.
Iraq's southern marshes had been home to a unique culture for centuries before Saddam's crackdown turned much of it to desert. Programmes to reflood the marshlands since the dictator's fall have seen some limited success in restoring lost habitats.