Decazeville in Aveyron (France) is a very old mining basin where from the 19th century on, several metallurgical factories settled. Some are still operating, 47 years after the closure of the last coal pit; most of the time, they have limited their activities while specialising in metal manufacturing and shaping, or the recycling of metallurgy scraps. The rich social history of the small twin cities of Decazeville and Viviez, ie. the development and closure of the mines and factories, as well as the struggles and strikes that came along have been well documented. However, very few scholars have addressed the issue of the industrial nuisances and the transformation which has impacted the cities and landscapes. Yet, the level of pollution generated by this industry is well known by the ecotoxicologists who study its effects on rivers all the way up to the Gironde estuary. High quantities of heavy metals, especially cadmium, have been scattered into the environment since the 19th century and are still mostly trapped in the sediments of the Riou Mort and Lot rivers. Nowadays, industrial processes have improved and most of the effluents are under control; nonetheless, the potential noxiousness of historical pollution remains able to affect large portions of territories with unequal vulnerabilities. The residents of the Decazeville basin were the first ones to be exposed to pollution, first and foremost to the smoke then to effluent that affected the surrounding soils and streams. Many of the testimonies that were collected during interviews mention appalingly bad smells, belongings corroded by acid rains or the decline of gardens and vegetation. Although it seems that beyond individual disapproval and compensation claims, no real public critique has emerged for a very long time. We had to wait until the local health services reacted, after being alerted by information about poor soil quality that started to circulate when a project for the remediation of an industrial wasteland was launched. Then, the questions of environmental pollution and human health were asked, generating huge controversy. An epidemiological survey was organised, arousing tensions between the different actors involved such as state and local administrative representatives, elected local representatives and the main industrial operator, a zinc manufacturer which was already engaging in remediation actions. The first results of this controversial survey were presented publicly in February 2010 in Viviez. However, we still don't know if the new information on cadmium contamination - which affects a small number of people significantly - will change the residents' relations with their industrial past and present and the related risks. This paper aims to question the production and circulation of knowledge on metallic pollution in a specific socio-historical context where city and industry are consubstantial. Our study broaches both long and short time periods i.e. it takes into account of the very historicity of the basin both in economic, political and social terms. Our objective is to show how metal pollution is thought about, measured, managed, contained and compensated at different times in history in relation to the knowledge that was available at the time. We investigate what blocked the production and circulation of knowledge about risks, whether expert or lay ones, as well as what were the effects of the framing of pollution as a risk either internalised or externalised. In conclusion, we discuss the way local residents talk about the industrial nuisances they had to suffer from and may express critiques despite the fact that they fear their territory could be reduced to this aspect.