The objective of this article is to present a series of 12 cases with the chronic lead poisoning produced after a short but intensive professional exposure (in average 12-14 hours per day, 41.6 days) at mineral dust and oxides containing lead (technical revision of a oven and of a furnace network by mechanical and welding operation). After the first case with saturnine colic, all the workers of the same team (n=12) were hospitalised (average time was of 14 days) with clinical examination and by specific toxicological indicators. Particularly, for clinical picture were uncharacteristic and oligosymptomatic complaints. Occupational exposure was augmented by the level of Pb-blood (46.8-286 mg/100 ml are ranges), Pb-urine (221-637 mg/l are ranges), d-aminolevulinic urinary acid (22.9-99.1 mg/l are ranges) and increased urinary coproporphyrins (+ +, + + +) exceeding biological limits and high urinary discharge of lead induced by CaNa2-EDTA treatment. The biological effects of lead intoxication consist in the occurrence of stippled basophilic erythrocytes (2 cases with 46,000/1 mil erythrocytes), the anemia (only 4 cases with haematocrit L 40%) and the liver cytolytic syndrome (the increase of GPT, GOT and of g-GT). These changes and the polyneuropathic syndrome (the decrease of motor and sensitive speed velocity) were judged by toxic combination between ethanol and lead.