Survivors of the Grenfell fire have demanded urgent meetings with ministers and senior health officials following revelations that significant amounts of toxins were found in soil close to the tower in preliminary findings of a major study.

The disclosures have prompted Grenfell United, which represents the families of the 72 people who died, to ask why no one who knew about the early results of the research had warned residents of the potential contamination problem.

In a letter to ministers, the Royal Borough of Kensington and Chelsea (RBKC) and Public Health England (PHE), the group’s chair, Natasha Elcock, said: “This has been a concern that Grenfell United have raised time and time again … we are deeply disturbed by this.”

The government said it was taking the issue seriously. “We recognise the community have concerns about the possibility of soil contamination following the Grenfell Tower fire,” said a spokesperson for the Ministry of Housing, Communities and Local Government.

“We are working closely with RBKC, Public Health England and other appropriate experts to ensure that any risks to health and wellbeing that might emerge will be promptly and effectively dealt with.”

The Guardian revealed on Friday that one of the world’s leading toxicology experts, Prof Anna Stec, was conducting an independent study into the dust and soil around the site in west London.

In briefings to senior health agency staff in the spring, Stec said she had found “huge concentrations” of potential carcinogens in residue around the tower and in burned debris that had fallen from it. High levels of hydrogen cyanide were also present in soil samples she analysed.

Stec, an expert in fire chemistry and toxicology who runs a team at the University of Central Lancashire, was recently appointed as an expert witness to the Grenfell Tower inquiry.

In February she privately urged PHE, the Department of Health, the police and the council to organise tests to ensure any potential health risks could be properly assessed.

Grenfell United said on Monday the health authorities needed to immediately explain “what the risks are and what action will be taken”.

In its letter, the group pointed out that a school near the tower, Kensington Aldridge Academy, had only been reopened after assurances to parents that “there were no health concerns for their children being in the footprint of the tower”. Children have been growing food in a community garden nearby.

RBKC said the council and health officials were now seeking “an urgent meeting with Professor Stec to discuss her study, its methodology and its implications”.

It said in a statement: “They will then undertake a rapid review of what, if any, further actions should be taken with regard to any soil contamination, in order to protect and reassure the public.

“The council will also be revisiting our records relating to historic land use and contamination to establish the baseline against which any new findings may be compared.”

RBKC said it had acted on the advice of PHE, which has been monitoring air quality around the tower and has consistently said nothing of concern was found.

Daily air monitoring and modelling of where the smoke plume travelled after the fire had not indicated a need for soil testing, the council said, though it reiterated its advice that locally grown fruit and vegetables “should be washed and peeled thoroughly before being eaten”.

“Also, anyone working or playing in soil should wash their hands well afterwards. This advice has not changed since before the Grenfell tragedy,” it said.

Stec told the Guardian she began her study last year in an effort to identify any potential health risks to survivors, residents and firefighters.

“As a result of this work, I already have datasets that indicate a number of toxins that have not yet been measured by PHE,” she said.

“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.”