Unknown to museum curators, a 1937 masterpiece by the French painter Raoul Dufy has for years concealed a thick layer of carcinogenic asbestos.
The painting, "La Fee Electricite", was commissioned by the Paris electricity company for the 1937 World Fair. It is one of the world's largest murals, measuring 60 metres long and 10 metres high. All of its 250 wood panels will be stripped of asbestos during the first half of next year.
Since 1964 the mural has been housed in a triangular room at the Paris Museum of Modern Art in the Palais de Tokyo, built with the neighbouring Trocadero complex by the left-wing Popular Front government in neo-classical 1930s style. It shows the history of electricity and science and is painted in the bright colours with black outlining typical of Dufy's work. The artist, who lived from 1877 until 1953, is best known for his scenes of horse races, regattas and the English Channel around his native Le Havre.
Curators stressed there was no danger to visitors because the painting came between them and the asbestos. The dangerous coating was discovered during a routine check of public buildings.
A recent French law bans all trace of the substance, which causes lung disease as well as cancer. Technicians have been removing asbestos from the Jussieu campus of the University of Paris for years, and Le Monde newspaper plans to vacate its headquarters because asbestos was found there.
The museum said no other art work is known to have been "protected" with asbestos. Nor is it known when the panels were sprayed. Over seven months from the end of this year, the carcinogenic insulation will be scraped away by technicians wearing masks and protective clothing, and immediately sucked into a vacuum. Because of the risk of damaging the fragile panels, art restorers will stand by. They will work inside a plastic bubble, and the process is expected to cost £840,336.
A curator at the Paris Modern Art Museum saw a paradox between the science and modernity praised in Dufy's painting and the unwitting, widespread use of asbestos as a fire retardant through much of the last century. She also contrasted the power and progress projected at the 1937 World's Fair with economic crisis and the rise of totalitarianism.
Dufy's mural was housed in the French pavilion on the Champs de Mars, designed by the modern architect, Robert Mallet-Stevens. A huge electrical spark flickered in front of the pavilion, which also contained the first wide-screen cinema.