Leading Aircraftman Ronald Maddison died at the base in 1953
Porton Down veterans used as guinea-pigs to test chemical weapons face no greater risk of dying from cancer but health worries remain, experts say.
The work, commissioned by the Ministry of Defence, provides some reassurance for the 18,000 plus British soldiers experimented on between 1941 and 1989.
It is the first time that the long-term health consequences have been explored.
The British Medical Journal studies show certain tumours may be more likely and death risk is very slightly raised.
Hundreds of Porton Down veterans believe their subsequent ill health may have been a result of their exposure in the secret government tests.
And relatives of some who have since died believe the trials may have led to premature deaths.
But many have reported no ill effects after being exposed to chemical and biological agents, including anthrax, sarin and mustard gas.
No lasting damage
The latest work tracked servicemen and women who took part in chemical tests at the Wiltshire laboratory and military personnel who were not included in the tests for an average of over 40 years.
Over 7,000 of the Porton Down veterans had died by the end of 2004 and their overall death rates were 6% higher than non-Porton Down veterans.
These excess deaths were mainly from infectious and parasitic diseases, genitourinary causes, circulatory diseases, and non-medical causes.
And some were probably related to the longer years of service carried out by the Porton Down veterans compared with other comrades.
Built in 1916 as an experimental base for research into chemical warfare
Initial testing focused on the effects of mustard gas
With WWII, efforts turned from chemical to biological weapons like anthrax
As the war ended, volunteers began testing the nerve-agent sarin - a practice that was to continue until 1989
There have been allegations of unethical human experimentation, such as those relating to the death of Leading Aircraftman Ronald Maddison in 1953
In 2002 a Ministry of Defence helpline is set up to enable veterans to find out more about the trials they were involved in
But cancer death rates were the same for both groups, although certain types of cancer, like lung cancer, were more common among the Porton Down veterans which may be linked to the types of chemicals tested.
Other research has shown that the veterans are more likely to experience unwanted symptoms and generally have a poorer quality of life than other soldiers.
Investigator Dr Lucy Carpenter, from the University of Oxford, said: ''What we have found is a small increase in overall death rates in the Porton Down veterans when compared with other veterans but no increase in overall cancer rates.
"Many of the Porton Down veterans have concerns about the effect that taking part in experimental tests will have had on their health.
"We hope the results of this independent study may help to answer some of their questions.''
The Ministry of Defence welcomed the findings. A spokeswoman said: "The nation owes a debt to those who took part in the trials at Porton Down.
"The studies played a key role in ensuring the protection of the UK and its Armed Forces against the very real threat of chemical or biological attack."