Local health teams were told to say that the metallic dust that has blighted Tilbury for months is nothing more than a “nuisance” despite leading health authorities not knowing if the statement was accurate, internal emails have revealed.

Thurrock’s Public Health teams were advised by a Public Health England consultant to tell Tilbury residents that the dark brown dust blanketing their homes and cars is “a nuisance but not believed to be a direct risk to health” in November last year.

But a raft of emails obtained by the Local Democracy Reporting Service show that at the same time authorities including Public Health England, the Port Health Authority and Thurrock Council, were debating whether the statement was true.

A follow-up email sent a month after the advice was given to the public health teams, Public Health England’s Environmental Hazards and Emergencies Department wrote that a “detailed assessment of the potential hazards associated with any exposure to the dust is difficult beyond general terms”.

The December email states: “Without information relating to the composition of the dust – i.e. the concentration and size fraction – a detailed assessment of the potential hazards associated with any exposure to the dust is difficult beyond general terms.”

It continues: “This could for those exposed, exacerbate short term health effects such as nose, throat and eye irritation and the symptoms of anyone with pre-existing respiratory conditions, such as asthma.

“It is not possible to offer a more definitive risk assessment in the absence of information about exposure – the extent of visible dust, reported symptoms, areas effects etc – or environmental monitoring data.”

It goes on to say a sample will help gauge the size of the dust particles, which will indicate whether there is a danger associated with it.

Small dust particles can be inhaled and result in short or long-term health effects, while larger particles can become trapped by the nose, throat or upper airways and are “unlikely to cause long term health effects”.

A crucial piece of advice that was not communicated to residents despite it being advised in many of the emails is that if residents are concerned about their health they should “seek medical advice from their GP or NHS”.

Public Health England’s mixed messages resulted in Councillor Aaron Watkins passing on advice that there is no health risk to the council and residents who had presented a petition.

Ian Wake, director of Thurrock Council’s Public Health Team, also emailed before the follow-up email in December, calling for a “collective council response to the community” because “rumour and mis-information are likely to multiply if the community is left to its own devices”.