The good clinical practice guidelines for the surveillance of workers after occupational exposure to lung carcinogens were approved by the Haute Autorité de la Santé (French National Authority for Health) and the Institut National du Cancer (French National Cancer Institute) in December 2015 and one recommendation of these guidelines concerns the setting-up of a trial of low-dose chest computed tomography (CT) lung cancer screening in subjects occupationally exposed to lung carcinogens at high-risk of lung cancer (Expert consensus). In LUCSO study, the investigators propose to conduct, under strictly defined conditions, a feasibility study of lung cancer screening in a population defined as being at high risk of lung cancer according to these good clinical practice guidelines. This population consists of smokers, aged from 55 to 74 years, currently or previously exposed to International Agency for Research on Cancer lung group 1 lung carcinogens. The primary objective of this study is to evaluate the complex organization of lung cancer screening in the target population. This evaluation will focus on the following indicators: * Screening activity indicator: screening coverage rate over two years * Test quality indicator: validity of self-administered questionnaires to target the high-risk population * Examination quality indicator: lung cancer detection rate, lung cancer detection rates by stage, validity of low-dose chest CT scan * Follow-up indicator: smoking cessation rate, mortality rate This trial will be conducted in 8 French departments, by six reference centers specialized in occupational health (SRC). In view of the exploratory nature of this trial, it is proposed to initially test the feasibility and acceptability of lung cancer screening sequentially over the first two years (Phase 1: 2021-2023, 24 months) in only two SRC (Val-de-Marne and Gironde). The trial will be conducted in several steps: 1. Identification of subjects currently or previously occupationally exposed to lung carcinogens by a screening invitation letter sent by Departmental Cancer Screening Centers to subjects aged from 55 to 74 years. 2. Evaluation of occupational exposure to lung carcinogens 3. Evaluation of the lung cancer risk level and verification of eligibility 4. Screening procedure: Chest CT scans will be performed by centers specialized in chest imaging 5. Lung cancer follow-up when an abnormality suggestive of lung cancer is demonstrated.