Soil tests around Grenfell Tower have reportedly revealed "huge concentrations" of potential carcinogens that could have health implications for the people who live and work close by.
Anna Stec, a leading toxicology expert who has conducted preliminary research seen by the Guardian, is also said to have found high levels of hydrogen cyanide in the soil and dust she analysed around the west London tower block.
The professor in fire chemistry and toxicity at the University of Central Lancashire has urged senior health officials, the police, and Kensington and Chelsea Council of the need for further tests.
She told the Guardian she had taken a high number of samples from locations up to almost a mile away from the tower.
"As a result of this work, I already have datasets that indicate a number of toxins that have not yet been measured by Public Health England (PHE), who have already looked into air quality," she told the paper.
"I think my research will show there are a number of added toxicants that need to be measured, but it's important to emphasise that this work has not yet been completed – and we still need to carry out a lot of analysis before we can be completely sure of the implications.
"The findings will need to be validated before they are published."
Seventy-two people died as a result of the fire on 14 June last year.
Last month, Professor Stec was instructed by the public inquiry into the blaze as an expert witness.
She will provide a report to determine the fire-derived toxicants and related deposits present in the tower and their origin.
A spokesman for PHE said the agency had not yet been briefed by the professor or seen her data.
The agency has been monitoring the air quality around the tower and has consistently said it has found nothing of concern.
A PHE spokesman said: "Local authorities are responsible for assessing and legally determining contaminated land within their communities.
"PHE is aware of Professor Stec's preliminary research but it has not been shared with us and therefore we have not had the opportunity to review the evidence being referred to.
"PHE awaits the research with interest and will carefully consider the results.
"We are continuing to fully support local health partners and the Grenfell community to ensure that they have access to best available public health evidence and advice for ongoing monitoring and surveillance of people directly impacted by the fire."
More from Grenfell Tower
Health chiefs recently announced that Grenfell survivors and surrounding residents are to be given special screening to examine the effects of smoke inhalation and possible asbestos exposure.
NHS England said it would provide up to £50m to fund long-term screening and treatment for those affected by the Grenfell fire.