In December 2008, a patient who had undergone surgery for kidney cancer reported, in a letter addressed to the Minister of Health, about a dozen similar cases at the Lavéra petrochemical complex where he had worked. A multidisciplinary technical committee recommended conducting a standard investigation of a spatiotemporal cluster in the workplace, as recommended by the InVS. Of the 15 reported cases, 10 were histologically confirmed kidney cancers that had been surgically treated between 2000 and 2007. The cases occurred in nine men and one woman, with an average age at diagnosis of 60 years. Most of them were no longer working at the time of diagnosis. Seven of the ten cases were exposed to multiple pollutants, as they had worked in several units at the Lavéra site during their careers. The most frequently cited units were the cracking units, the butadiene unit, the CVM workshop, and the chlorine workshops. To determine whether there was an excess of kidney cancer cases at the Lavéra platform, we calculated the age-standardized incidence rate of kidney cancer among employees of companies at the Lavéra platform between 1994 and 2007. To account for cases occurring after retirement, we counted the person-years of active workers and the person-years weighted by all-cause mortality rates for a reconstructed cohort of retirees. Since only one case was reported in a woman, the analysis was conducted for men only. Thus, 6 cases of kidney cancer were observed in men during the 1994–2007 period, whereas 7.3 cases were expected for an incidence equal to that of the French population (SIR = 0.8; 95% CI [0.3–1.9]). This analysis did not reveal an excess of kidney cancer cases at the Lavéra platform. (R.A.)