The vehicle carried radiation warning signs and was filled with containers marked "wartime use only". Concerned, Mr Kenny contacted his MP and discovered that what he had seen were depleted uranium munitions bound for the nearby Dundrennan military testing range.
Since 1982 more than 6,000 DU shells have been fired from the range at the south-western tip of Scotland into the Solway Firth. Most of the shells, some 20 tonnes worth, are still lying on the seabed. Only one has been retrieved.
The testing is carried out by the defence evaluation and research agency and is due to stop this October. The agency says it is done under strictly controlled conditions and a comprehensive monitoring programme launched in 1983 has shown only very low levels of DU contamination at the base, well below anything that could be considered a health hazard.
But local people tell a different story. They say there have been misfirings on the remote 4,500-acre range. Some claim the site is littered with unexploded ordnance; that there has been a strange red dust on the road that borders the base; that a quartermaster died of leukaemia.
There are reports of traces of beryllium, a component of depleted uranium, being found 30 miles away from Dundrennan; and in 1995 an independent report recommended that special monitors were set up outside the base, something locals say has not been done.
Mr Kenny is 80. A wartime bomb disposal officer and retired oil executive, he now devotes his time to discovering the truth about DU and its effect on the community.
"The local people have always believed me, but the rest saw me as an eccentric old man with a particularly irritating bee in his bonnet," he said.
"It has taken 17 years out of my retirement and I was intending to go fishing every day. Now my study is full of documents and I rarely have time to do anything else."
Mr Kenny wants a full public inquiry into the DU testing and a comprehensive independent health screening programme for local people.
Local politicians have called for the testing to stop, and on Thursday, Malcolm Hooper, of the Gulf war illnesses inter-parliamentary group, said he was concerned about the impact of the manufacture and testing of the DU munitions.
"I don't want to scaremonger but I think there is a real risk - it's unquantifiable and if I lived in such an area where there was production or firing, I would be worried," Professor Hooper said.
Officials at the Military Toxics Project, an American environmental pressure group that monitors sites across the US where DU weapons are manufactured and tested, say Mr Kenny is right to be worried.
"The local community should be concerned," said MTP national organiser, Tara Thornton. "There are areas here in the US where we work with communities that live around the proving grounds and the manufacturing sites and we have seen increased rates of cancer in these areas. The big problem is that the proper health studies have not been done. There needs to be much more in-depth health studies done in these areas."
Mr Kenny claims to know of a cluster of cancers in the area around Dundrennan, but local health officials who have checked leukaemia rates say there is nothing of statistical significance.
David Breen, consultant in public medicine for Dumfries and Galloway health board, said statistics from 1980 to 1997 showed no evidence of a high risk of leukaemia in children living near the range. Dr Breen has asked the Scottish cancer surveillance unit to update the figures to include 1998, and they will be made public in the next few days. "If there is an excess I would be worried, but at the moment there isn't," he said.
Meanwhile, environmentalists say efforts must be made to recover the DU shells littering the seabed in the Solway Firth. The area is rich in shellfish and there have been reports of fishermen picking up DU shells in their nets.
"If there are particles of DU floating about then the shellfish will ingest them and there is a clear route by which people could be affected," said Dr Richard Dixon of Friends of the Earth. "We now have a strong suspicion that our service people have been affected by this stuff. That is as close as you get to a smoking gun.
"Our view is that in the end the MoD will have to admit defeat and retrieve as much of this stuff as possible. We are only going to get more concerned about DU."
Mr Kenny has always been worried. But he feels no vindication that others now share his fears.
"I'm just very angry it has taken so long. I don't give a damn about people my age. It's the future generations that concern me. We need to get this sorted out for their sake."