European leaders have been warned they are not sufficiently prepared to deal with a terrorist chemical attack.
Experts say the necessary public health staff levels and resources aren't yet in place to respond to a major incident.
Dr Dinko Kello, chemical safety adviser for the World Health Organisation, says nations have to work together to minimise the impact of a terror attack.
Speaking in Cardiff at an international conference on preparations for chemical incidents, he said: "There is no such thing as a fool-proof safety system.
"Therefore there must be an appropriate response system to minimise the impact of a terror attack.
"Public health is under-resourced and under-staffed in many countries and they would be unable to take on the additional burden of responding to a terror attack."
Dr Kello says the anthrax attacks in the US were the only incidents of a deliberate chemical attack over the past year.
But he said there had been more than 200 other forms of terror attacks in Europe.
The WHO has set out a list of recommendations to improve the response to a chemical terror attack.
PA