Two adverts warning cigarette smoke contains the radioactive substance that killed Russian spy Alexander Litvinenko has been pulled from a health campaign.
Manchester undertaker Russell Hopps was shocked to hear formaldehyde was found in cigarettes
The Department of Health said it was "inappropriate" to show the ad, which shows cigarettes contain polonium 210.
Experts are testing people who had contact with Mr Litvinenko or went to the same places to see if they were also infected.
But other adverts in the 'Smoke is Poison' campaign will air as planned.
The series of radio and television adverts, funded by the Department of Health and backed by Cancer Research UK, are fronted by investigative journalist Donal MacIntyre.
Each involves him interviewing someone exposed to a dangerous substance, including formaldehyde and benzene, in their work about the measures they take to protect themselves.
The interviewee is then told that cigarettes contain the same chemical.
Sara Hiom, deputy director of cancer information, said the decision to withhold the adverts focussing on polonium 210 was taken jointly with the Department of Health.
"In light of recent unforeseen events and in consultation with the Department of Health, we took the decision not to air the polonium advert at this time.
"Information about polonium in relation to the campaign does feature elsewhere, such as on the campaign website www.smokeispoison.com."
A Department of Health spokeswoman: "When the Health Protection Agency confirmed that Mr Litvinenko had died from Polonium 210 poisoning we began discussions about the content of the 'Smoke is Poison' campaign.
"Because two of the five ads contained references to Polonium in cigarettes we took the decision with Cancer Research UK to withdraw these ads from this campaign.
"The remaining ads have hard-hitting messages about the dangers of cigarette smoke and the poisonous substances it contains"
The campaign also includes posters and beer mats.
Some mats which were sent out early to pubs in the West Country, saying 'Where do you find polonium? In cigarettes'.
They caused some concern locally, and have now also been withdrawn.