Visitors to the Houses of Parliament, MPs, peers and officials working in the 170-year-old building are at risk of exposure to a dangerous form of asbestos fibres, according to a safety report seen by the Guardian.
A detailed investigation of the service shafts and piping ducts hidden behind the neo-Gothic committee rooms and chambers warns of "significant dangers" to "all persons" in the Palace of Westminster.
The study - produced by Goddard Consulting, London-based health and safety experts, for the Parliamentary Works Service Directorate - was delivered earlier this year. It documents fears that risks are not being adequately addressed.
One problem identified was an access door to an asbestos-contaminated shaft beside the Commons kitchen that was wedged shut with a spoon and was often opened when the room became too hot.
"On opening this door cold air rushed in and it was like standing in a wind tunnel," the report, obtained by the medical technology magazine Clinica, states. "Asbestos fibres would be readily dispersed in the kitchen areas if the dust and debris was disturbed in the riser in any way."
The survey team only entered the shaft wearing protective clothing and breathing masks.
Unsecured access doors were regularly discovered. An email, dated last October and reproduced in the study, suggests rising levels of frustration among the consultants.
One said: "In view of the fact that in December 2006 I issued a report on the risers [service shafts] warning of the consequences of riser access doors being unlocked and unsealed, the Palace of Westminster authorities may wish to consider whether or not they have taken adequate steps to protect employees and visitors from exposure to asbestos fibres in accordance with the Control of Asbestos Regulations 2006."
Of 20 samples taken last August from four service shafts, 11 showed the presence of "amosite" in debris on the floor or walls. Amosite, or brown asbestos, is one of the more dangerous forms of the potentially carcinogenic mineral.
As a result of the inspections, the report, says: "We became aware of significant dangers and risks to the health and safety of persons not only gaining access and working in the risers and ducts but generally to all persons within the Palace of Westminister."
An earlier draft of the report, dated December 2006, said many of the risers had "airborne asbestos fibres present" and - because inadequately secured - "there is a serious risk of asbestos contamination of many areas and offices".
Among its recommendations is that access doors to shafts should be locked and the keys held centrally.
The use of asbestos as an insulating material in the sprawling recesses of the building has been previously acknowledged. An internal survey was carried out in 2005 and MPs were reassured that asbestos had been safely contained.
During a debate in the Lords on March 8 2007, peers were informed that 200 asbestos sites had been identified. A thousand air tests were carried out at more than 40 of those sites, all returning "below the detectable fibre count limit of 0.01 fibres per millilitre".
In response to questions from the Guardian, a spokeswoman for the Palace of Westminster confirmed that a survey of risers was carried out in 2007.
"The most significant risks identified were dealt with as a matter of urgency," she said. "The kitchen cupboard was identified on October 26 2007 and the door was relocked within 24 hours. The lock was later replaced ... The associated level of risk to kitchen staff when the riser cupboard was open is considered to be minimal ... All but one of the riser cupboards used by the cleaning staff are free of asbestos and are compartmentalised, inhibiting any airflow from other sections of that riser."
A House of Commons spokesman said last night: "The letter from Goddard Consulting quite understandably drew our attention to the fact that we had not implemented all the recommendations within their 2005 report. That is correct. However, this is a complex area where professional opinions may differ. There are a number of recommendations where we felt that alternative ways of managing the hazard would be equally effective and the problems were addressed accordingly."
Asbestos is widespread in older buildings. According to the Control of Asbestos Regulations 2006, it may be left in place safely as long as its condition is monitored and it is not disturbed. The Health and Safety Executive describes asbestos as the greatest single cause of work-related deaths in the UK. The number of deaths from asbestos-related cancers is expected to peak at around 2,450 a year by 2015.