Police briefly cordoned off part of the English city of Salisbury on Thursday near where former Russian double agent Sergei Skripal and his daughter were found poisoned, then removed the barriers after discovering no cause
Police had said they were dealing with an incident involving a man in his 30s as part of "highly precautionary measures" put in place in view of the poisoning of the Skripals in March and of two British people last week.
Last week the two people were found poisoned in a town near Salisbury by the same Novichok nerve agent used against the Skripals. One of the two, Dawn Sturgess, 44, died Sunday.
Thursday's incident proved a false alarm, however.
"Emergency services were called to the scene at 6:20 p.m. (1720 GMT) this evening after concerns were raised about the welfare of a man in his 30s," Salisbury police said on its Facebook page. "We can now confirm that there is no concern for either his health or any wider risk to the public."
The poisoning of the Skripals with the Soviet-developed nerve agent Novichok plunged British-Russian relations to their lowest point since the end of the Cold War.
Yulia Skripal, Sergei's daughter, was in a coma for 20 days after she was attacked and was eventually discharged about five weeks after the poisoning. Her father was discharged on May 18.
The poisoning of the Skripals was the first known offensive use of such a chemical weapon in Europe since World War II.
Russia has denied any involvement in the Skripal case and suggested the British security services carried out the attack to stoke anti-Moscow hysteria, an assertion London calls absurd.