Physical risk (Green) – Group 1 Noise; Vibration; Ionizing radiation; Non-ionizing radiation; Cold; Heat; Abnormal pressure; Humidity. Chemical risk (Red) – Group 2 Dust; Fumes; Mist; Fog; Gases; Vapors; Substances, compounds or chemical products in general. Biological risk (Brown) – Group 3 Viruses; Bacteria; Parasites; Fungi; Toxins and poisons, allergens; Prions. Ergonomic risk (Yellow) – Group 4 Intense physical effort; Lifting and transporting weight; Inadequate posture; Strict control of productivity; Enforcement of excessive working pace; Working day and night; Extended working hours; Monotony and repetitive activity; Other conditions that cause physical and/or psychological stress. Accidental risk (Blue) – Group 5 Inappropriate physical arrangement; Machinery and equipment operated without protection; Inadequate lighting; Electricity; Probability of fire or explosion; Inadequate storage; Poisonous animals; Other situations in which risk may contribute to the occurrence of accidents.

Table 1: Classification of the main occupational risk groups according to their nature and the standardization of corresponding colors. Source: Modified from the NR32-MTE-Brazil and Ordinance No. 25, December 29th in 1994, MTE-Brazil. *Republished due to incorrectness of the original, in the Diário Oficial of 30/12/94, Section 1, pp 21280-21282. Republished on 15/12/95 - Section 1 - pp 1987-1989, Ministry of Labor and Security Secretariat Employment and Health.