Work-related musculoskeletal disorders (WRMDs) are heterogeneous organic and functional disorders that are developed in the exercise of labor activities. In Brazil, these diseases are responsible for a large part of work absence, according to the statistical database of the National Institute of Social Security (INSS) and classified by the International Classification of Diseases (ICD) in 2017 were framed more than twenty-two thousand cases insured for the Brazilian government. During the on-site evaluation in a heavy metallurgical industry using ergonomics tools, it was possible to observe that up to 60% of the manual tasks developed, presented dysfunctional conditions to the specifications of hygiene and occupational health. It was found that upper limbs such as shoulders, neck, wrists, waist and spine, besides having high potential for the development of musculoskeletal disorders by diffuse, repetitive and overloaded movements, proved tasks with abrupt flexion outside of the standards recommended by the international health and safety organizations. The evaluation was carried out in a case study with the formulation of the Ergonomics Analysis, where the angles and frequencies of specific performance of the limbs were observed and classified into distinct groups for normal, moderate and severe activities, assigning a numerical classification. This article aims to anticipate and recognize the hazards in working conditions by correlating daily activities applying NIOSH techniques and recommendations, using the Rapid Upper Limb Assessment (RULA) method to evaluate ergonomic risks and to suggest actions in according to the Lean Philosophy to minimize the impact of operational handling on worker health.