At least seven people died and three were injured when a Chinese-owned clothing factory in an industrial zone in the Italian town of Prato burned down on Sunday, killing workers trapped in an improvised dormitory built onsite.
Local media said 11 workers had been accommodated in a warren of small cardboard sleeping compartments above a warehouse.
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"This is a disgrace for all of us, because we have to recognize this reality for what it is: the biggest concentration of illegal employment in northern and central Italy," said Enrico Rossi, president of the region of Tuscany.
Footage posted on the website of the local Il Tirreno newspaper showed fire crews battling the flames in a warehouse-like structure while smoke poured out of the building. Ambulances and police vehicles were also on the scene.
The disaster prompted immediate questions about the conditions on the site and in a network of similar workshops operating in the area, which is noted for its large number of Chinese-owned textile manufacturing businesses, many operating on the fringes of legality.
"No one can say they are surprised at this because everyone has known for years that, in the area between Florence and Prato, hundreds if not thousands of people are living and working in conditions of near-slavery," Roberto Pistonina, secretary general of the Florence and Prato section of the CISL trade union, said on his Facebook page.
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The Macrolotto industrial district of Prato, just outside Florence, is known for its hundreds of Chinese-owned wholesalers and workshops turning out cheap clothing for the export market as well as well-known retail chains.
Prato is considered to have the highest concentration of Chinese immigrants in Italy, with at least 15,000 legally registered in a total population of under 200,000, according to official data. Thousands more are believed to be living in the city illegally.