Annex 12 of NR15 – Tolerance Limits for Mineral Dusts

(SSST Ordinance No. 01, of May 28, 1991)


1. This Annex applies to all activities in which workers are exposed to asbestos during their work.

    1.1. “Asbestos,” also known as amianthus, refers to the fibrous form of silicate minerals belonging to the groups of metamorphic rocks called serpentines, which includes chrysotile (white asbestos), and amphiboles, which include actinolite, amosite (brown asbestos), anthophyllite, crocidolite (blue asbestos), tremolite, or any mixture containing one or more of these minerals.

    1.2. “Asbestos exposure” refers to occupational exposure to respirable asbestos fibers or asbestos dust suspended in the air, originating from asbestos or minerals, materials, or products containing asbestos.

    1.3. “Asbestos supplier” refers to the producer and/or distributor of the raw material in its natural state.

    2. Whenever two or more employers, each with their own legal personality, carry out activities at the same workplace, the contracting and contracted parties will be jointly responsible for applying the legal provisions set forth in this Annex.

      2.1. It is the responsibility of the contracting party to ensure that the contracted party complies with the legal provisions set forth in this Annex.

      3. Employers must establish procedural norms to be adopted in emergency situations and appropriately inform the workers, including specific training.

        3.1. “Emergency situations” refer to any unscheduled events within the usual work process that imply an increase in worker exposure.

        4. The use of any type of amphibole asbestos and products containing these fibers is prohibited.

          4.1. The competent authority, after prior consultation with the most representative organizations of employers and workers concerned, may authorize the use of amphiboles, provided that substitution is not feasible and that health protection measures for workers are ensured.

          5. The spraying (spray) of all forms of asbestos is prohibited.

          6. Employment of individuals under eighteen years of age in sectors where they may be exposed to asbestos dust is prohibited.

          7. Companies (public or private) that produce, use, or market asbestos fibers and those responsible for removing systems that contain or may release asbestos fibers into the environment must register their establishments with the Ministry of Labor and Social Security/National Institute of Social Security, through its competent sector in matters of worker safety and health.

            7.1. This registration will be obtained by submitting the model in Annex I.

            7.2. The obtained registration number must be presented when purchasing the raw material from the supplier.

            7.3. Asbestos suppliers may only deliver the raw material to registered companies.

            7.4. Public bodies responsible for authorizing the importation of asbestos fibers may only issue import permits to registered companies.

            7.5. The registration must be updated every 2 (two) years.

            8. Before starting removal and/or demolition work, the employer and/or contractor, in conjunction with worker representatives, must prepare a work plan specifying the measures to be taken, including:

            a) Providing all necessary protection to workers;

            b) Limiting the release of asbestos dust into the air;

            c) Ensuring the disposal of asbestos-containing waste.

            9. Asbestos suppliers, as well as manufacturers and suppliers of products containing asbestos, are responsible for proper and sufficient labeling that is easily understandable by workers and users.

              9.1. The labeling must include, according to the Annex model:

              • The lowercase letter “a” occupying 40% (forty percent) of the total label area;
              • Characters: “Attention: contains asbestos,” “Inhaling asbestos dust is harmful to health,” and “Avoid risk: follow usage instructions.”

              9.2. The labeling must, whenever possible, be printed on the product, in a contrasting color, and be visible and legible.

              10. All products containing asbestos must be accompanied by “usage instructions” including at least the following information: type of asbestos, health risks and related diseases, control measures, and appropriate protection.

              11. The employer must conduct an environmental assessment of asbestos dust in the workplace at intervals not exceeding 6 (six) months.

                11.1. Assessment records must be kept for at least 30 (thirty) years.

                11.2. Worker representatives will monitor the environmental assessment process.

                11.3. Workers and/or their representatives have the right to request a supplementary environmental assessment in the workplace and/or challenge the results of the assessments with the competent authority.

                11.4. The employer is obliged to post the results of these assessments on a designated notice board for worker information.

                12. The tolerance limit for respirable chrysotile asbestos fibers is 2.0 f/cm³.

                  12.1. “Respirable asbestos fibers” are those with a diameter less than 3 micrometers, length greater than 5 micrometers, and a length-to-diameter ratio greater than 3:1. (Amended by SSST Ordinance No. 22, dated December 26, 1994)

                  13. The environmental assessment will be conducted using the membrane filter method, with magnifications of 400 to 500x, with phase contrast illumination.

                    13.1. Respirable fibers will be counted as specified in subitem 12.1, whether or not they are attached to or aggregated with other particles.

                    13.2. The assessment method to be used will be defined by ABNT/INMETRO.

                    13.3. Laboratories performing analyses of environmental samples of airborne fibers must certify participation in laboratory quality control programs and their ability to conduct analyses required by the membrane filter method. (Included by SSST Ordinance No. 22, dated December 12, 1994)

                    14. The employer must provide, free of charge, all work clothing that may be contaminated by asbestos, and this clothing must not be used outside the workplace.

                      14.1. The employer is responsible for the cleaning, maintenance, and storage of work clothing, as well as the PPE used by the worker.

                      14.2. Work clothing must be changed at least twice a week.

                      15. The employer must provide double lockers for workers exposed to asbestos.

                        15.1. “Double lockers” refer to facilities offering one area for storing personal clothing and another, isolated area for storing work clothing, both directly connected to the shower area.

                        15.2. Other construction and installation specifications must comply with the determinations of other Regulatory Standards.

                        16. At the end of each workday, the employer must create conditions for workers to change clothes and shower.

                        17. The employer must dispose of asbestos-containing waste in a manner that does not pose any risk to the health of workers and the general population, in accordance with legal provisions set by competent environmental and other regulatory bodies.

                        18. All workers performing or involved in occupational exposure to asbestos will undergo medical examinations as provided in subitem 7.1.3 of NR-7. Upon hiring, dismissal, and annually, complementary examinations must be carried out, including, in addition to clinical evaluation, chest X-ray and pulmonary function test (spirometry).

                          18.1. The technique used for chest X-rays must comply with the standard determined by the International Labor Organization, specified in the International Classification of Radiographs of Pneumoconioses (ILO-1980).

                          18.2. Companies are obliged to inform workers of the results of the examinations conducted, using a specific form.

                          19. The employer must ensure the periodic availability of medical examinations for workers for 30 (thirty) years after the termination of the employment contract involving asbestos exposure.

                            19.1. These examinations must be conducted with the following frequency:

                            a) Every 3 (three) years for workers with an exposure period of 0 (zero) to 12 (twelve) years;

                            b) Every 2 (two) years for workers with an exposure period of 12 (twelve) to 20 (twenty) years;

                            c) Annually for workers with an exposure period of more than 20 (twenty) years.

                            19.2. Workers will be notified upon dismissal and during subsequent returns of the date and location of the next medical evaluation.

                            20. The employer must provide information and training to workers at least annually, prioritizing the risks and protection and control measures due to asbestos exposure.

                              20.1. Legally mandated prevention programs (CIPA course, SIPAT, etc.) must include specific information on the risks of asbestos exposure.

                              21. Notification deadlines and violation values are specified in Annex III.

                              22. The requirements contained in this annex will come into effect 180 (one hundred and eighty) days after the date of its publication, revoking any contrary provisions.

                              Annex 1
                              ASBESTOS USER REGISTRATION MODEL

                              I – IDENTIFICATION
                              Postal Code:
                              Business Sector:

                              II – PRODUCTION DATA

                              1. Number of Workers
                              • Total:
                              • Minors:
                              • Women:
                              • In direct contact with asbestos:
                              1. Asbestos Source
                              • Domestic
                              • Imported

                              Name of Supplier(s):

                              1. Manufactured Products
                              Type of product containing asbestosIntended use
                              1. Remarks:

                              NOTE: The above statements are the sole responsibility of the company, subject to verification and any penalties provided by law.


                              Signature and stamp:

                              Annex II

                              Annex III

                              Item and SubitemDeadlineInfraction
                              7, 7.2, 7.4P1I3
                              9, 9.1, 9.2P4I3
                              11, 11.1, 11.2 and 11.4P4I3
                              14, 14.1, 14.2P3I3
                              18, 18.2P3I2
                              19, 19.1P1I1
                              20, 20.1P1I1

                              MANGANESE AND ITS COMPOUNDS
                              (Included by DNSST Ordinance No. 08, of October 5, 1992)

                              1. The tolerance limit for operations involving manganese and its compounds related to extraction, treatment, grinding, transportation of ore, or other operations with exposure to manganese dust or its compounds is up to 5 mg/m³ in the air, for work shifts of up to 8 (eight) hours per day.

                              2. The tolerance limit for operations involving manganese and its compounds related to the metallurgy of manganese minerals, manufacture of manganese compounds, manufacture of batteries and dry cells, manufacture of special glass and ceramics, manufacture and use of welding electrodes, manufacture of chemical products, paints and fertilizers, or other operations with exposure to manganese fumes or its compounds is up to 1 mg/m³ in the air, for work shifts of up to 8 (eight) hours per day.

                              3. Whenever tolerance limits are exceeded, activities and operations involving manganese and its compounds will be considered as highly hazardous.

                              4. Payment of the hazard premium by the employer does not exempt them from adopting preventive and control measures to minimize workplace risks.

                              5. Environmental concentration assessments and hazard characterization can only be performed by a safety engineer or occupational physician as provided in art. 195 of the CLT.

                              6. The following recommendations and preventive control measures are indicated for operations involving manganese and its compounds, regardless of whether tolerance limits have been exceeded:

                                • Substitution of dry drilling with wet processes;
                                • Adequate ventilation after detonations before resuming work;
                                • Adequate ventilation during work in confined areas;
                                • Use of respiratory protection equipment with mechanical filters for contaminated areas;
                                • Use of respiratory protection equipment with supplied air lines for short periods in highly contaminated areas;
                                • Use of self-contained breathing apparatus for special cases and specific training;
                                • Rotation of activities and work shifts for drillers and other strenuous tasks;
                                • Dust control at levels below the permitted limits.

                                7. The following medical and hygiene precautions are mandatory for all workers exposed to operations involving manganese and its compounds, regardless of whether tolerance limits have been exceeded:

                                  • Pre-employment and periodic medical examinations;
                                  • Additional examinations for prolonged absenteeism, illness, accidents, or other cases;
                                  • Non-admission of employees with organic respiratory lesions, central nervous system conditions, and blood dysfunctions to work with manganese exposure;
                                  • Periodic examinations according to the type of activity of each worker, ranging from 3 (three) to 6 (six) months for underground work and from 6 (six) months to annually for surface workers;
                                  • Biological analysis of blood;
                                  • Immediate removal of individuals with symptoms of intoxication or neurological or psychological changes;
                                  • Mandatory shower after the work shift;
                                  • Change of clothes (work/personal/work);
                                  • Prohibition of eating in the workplace.

                                  CRYSTALLINE SILICA
                                  (Included by DNSST Ordinance No. 08, dated October 5, 1992)

                                  1. The tolerance limit, expressed in millions of particles per cubic decimeter, is given by the following formula:

                                    L.T. = 8.5 / (% quartz + 10) mppdc

                                    This formula is valid for samples taken with an impinger at the respiratory zone level and counted using bright field technique. The percentage of quartz is determined through air suspension samples.

                                    2. The tolerance limit for respirable dust, expressed in mg/m³, is given by the following formula:

                                      L.T. = 8 / (% quartz + 2) mg/m³

                                      3. Both the concentration and the percentage of quartz, for the application of this limit, must be determined from the portion that passes through a selector with the characteristics of Table No. 1.

                                        Table 1

                                        Aerodynamic Diameter (µm) (unit density sphere)% Passage by Selector
                                        ≤ 290
                                        10.00 (zero)

                                        4. The tolerance limit for total dust (respirable and non-respirable), expressed in mg/m³, is given by the following formula:

                                          L.T. = 24 / (% quartz + 3) mg/m³

                                          5. “Quartz” will always mean crystalline free silica.

                                          6. The tolerance limits set in item 5 are valid for workweeks of up to 48 (forty-eight) hours.

                                            6.1. For workweeks exceeding 48 (forty-eight) hours, the limits must be reduced, and these values set by the competent authority.

                                            7. The work process of sandblasting using dry or wet sand as an abrasive is prohibited. (Included by SIT Ordinance No. 99, of October 19, 2004)

                                            8. Machines and tools used in cutting and finishing ornamental stones must be equipped with a humidification system capable of minimizing or eliminating dust generation from their operation. (Approved by SIT Ordinance No. 43, of March 11, 2008)

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