In Owen Thetford's book, 'Aircraft of the RAF' pp338, he mentions that one of the last actions of the Vengeance in RAF service was "chemical warfare experiments" conducted by No.110 Squadron in East Africa in 1944.
Personnel of 110 (H) Detachment, RAF Takoradi, September 8 to December 4, 1944.
I can only assume, based on an article in Air Enthusiast No.71 by Don Neate, that he is referring to 'insecticide.' A combination of DDT and oil was poured into American MIO tanks for spraying over mosquito infected areas and the best method for spraying was to be investigated.
A number of problems arose. The major one being speed. It was found that the best speed for spraying, was less than 220mph. This proved too low for the Vengeance as it tended to fly in a nose-up attitude affecting vision and being somewhat dangerous in an area of broken terrain and tall single cotton trees. Flights had to be conducted above 220mph, but this produced "high shatter on the charge."
Serviceability of the Vengeance throughout the trials remained high, around 85%, despite remote conditions. The most effective formation for spraying turned out to be a 'V' formation of five aircraft.
Once on the ground the process of refuelling and 'rebombing' an aircraft was only five minutes.
Results showed that the methods employed were practical but the number of mosquitoes killed in the areas sprayed were not as high as expected.
The spraying trials ceased on November 1944. All flying ceased on December 2. A day later the Flight was closed down and the crews were posted to Home Establishment. According to the author the nine Vengeances involved in the trial were .."left there, either to rot, or awaiting disposal-one never knows, they may still be there."