" Amb. Ekeus - did you restart VX production after the Iran-Iraq war?
General Hussein Kamal - we changed the factory into pesticide production. Part of the establishment started to produce medicine.
Smidovich asked if the General was referring to the Samarra Drug Establishment.
General Hussein Kamal - Samarra started to produce medicine with workers from Muthanna. Muthanna itself started production of pesticides and insecticides, but some of them turned out to be more difficult to produce than CW. "
http://www.globalsecurity.org/wmd/library/news/iraq/un/unscom-iaea_kamal-brief.htm
So according to Kamal, Iraq has converted chem weapon plants to pesticide production before.
" PART ONE: Chapter 2: Iraq's Programmes: 1971-1988
1. Iraq has been involved in chemical and biological warfare research for over 30 years. Its chemical warfare research started in 1971 at a small, well-guarded site at Rashad to the north-east of Baghdad. Research was conducted there on a number of chemical agents including mustard gas, CS and tabun. Later, in 1974 a dedicated organisation called al-Hasan Ibn al-Haitham was established. In the late 1970s plans were made to build a research and commercial-scale production facility in the desert some 70km (42 miles) north west of Baghdad under the cover of Project 922. This was to become Muthanna State Establishment, also known as al-Muthanna, and operated under the front name of Iraq's State Establishment for Pesticide Production. It became operational in 1982-83. It had five research and development sections, each tasked to pursue different programmes. In addition, the al-Muthanna site was the main chemical agent production facility, and it also took the lead in weaponising chemical and biological agents including all aspects of weapon development and testing, in association with the military. According to information, subsequently supplied by the Iraqis, the total production capacity in 1991 was 4,000 tonnes of agent per annum, but we assess it could have been higher. Al-Muthanna was supported by three separate storage and precursor production facilities known as Fallujah 1, 2 and 3 near Habbaniyah, north-west of Baghdad, parts of which were not completed before they were heavily bombed in the 1991 Gulf War. "
http://www.al-bab.com/arab/docs/iraq/dossier02a.htm
It looks like Iraq was producing its chemical weapons in pesticide facilities from almost the very start.