Occupational Disease Notification Mexico (Aviso de Enfermedad Profesional)

An Occupational Disease Notification Mexico (Aviso de Enfermedad Profesional) is the formal document through which an employer identifies, investigates, and reports a suspected or confirmed occupational disease (enfermedad de trabajo or enfermedad profesional) — a health condition arising from the nature of the worker's occupation, the conditions of the work environment, or prolonged exposure to workplace hazards — as defined by Article 475 of the Ley Federal del Trabajo (LFT) and Article 41 of the Ley del Seguro Social (LSS).

Article 475 of the Ley Federal del Trabajo defines enfermedad de trabajo as every pathological state derived from continuous action of a cause having its origin or motivation in the work or environment in which the worker is obligated to provide their services, and determined by the Ley del Seguro Social and its regulations. This broad definition anchors occupational disease recognition in the LSS framework, which provides the definitive list of recognized occupational diseases and the IMSS classification and benefit system.

The Ley del Seguro Social Articles 41 through 48 govern occupational risks (riesgos de trabajo), of which enfermedades de trabajo are one category (alongside accidentes de trabajo). Article 41 LSS defines riesgo de trabajo as any accident or disease to which workers are exposed by reason of their work. Article 43 LSS provides that occupational diseases are those listed in the Tabla de Enfermedades de Trabajo — a regulatory annex to the LSS that currently lists 161 occupational diseases grouped by causal agent — and any others that the IMSS Comité Consultivo Nacional de Normalización de Seguridad Social determines to be of occupational origin. This list includes: pneumoconioses (silicosis, asbestosis, coal-worker's pneumoconiosis), noise-induced hearing loss (hipoacusia), contact dermatitis, repetitive strain injuries, chemical agent intoxications (lead, mercury, organic solvents), and — increasingly recognized by IMSS and Tribunales Laborales — psychological disorders (anxiety, depression, burnout) caused by identified psychosocial risk factors measurable under NOM-035-STPS-2018.

Unlike workplace accidents (which occur suddenly and require IMSS notification within 24 hours under LSS Article 51), occupational diseases develop gradually over months or years of workplace exposure. The IMSS notification procedure for occupational diseases uses the IMSS ST-9 form (Aviso para Calificar Probable Enfermedad de Trabajo), submitted by the employer within 24 hours of becoming aware of the diagnosis — whether through a worker's medical leave request, a medical certificate from a treating physician, or the IMSS's own medical services. The IMSS then conducts a calificación del riesgo to determine whether the disease is of occupational origin, reviewing the worker's work history, exposure records, and medical documentation.

Article 504 of the Ley Federal del Trabajo establishes general employer obligations following any occupational risk — including diseases — to provide first assistance and to report to the STPS. The Comisión Mixta de Seguridad e Higiene (Joint Safety and Hygiene Commission, Articles 509–514 LFT) must also investigate occupational disease cases to identify workplace exposure sources and recommend preventive measures. NOM-021-STPS-1994 requires that occupational disease cases be included in the employer's accident and disease statistics maintained for STPS inspection purposes.

An Occupational Disease Notification Mexico must be completed every time an employer has reason to believe that a worker has contracted or is developing a disease of occupational origin — whether the worker self-reports symptoms, a private physician issues a medical certificate attributing a condition to workplace exposure, the IMSS medical services make a preliminary diagnosis, or the employer's occupational health service (servicio médico de empresa) identifies a pattern of illness among workers in a specific area.

The notification is urgently needed when a worker presents a medical certificate (certificado médico) or IMSS medical disability document (incapacidad temporal) that attributes their condition to a workplace hazard — the employer must file the IMSS ST-9 form within 24 hours of receiving this documentation under the LSS notification framework, regardless of whether the employer agrees with the occupational origin classification.

An Occupational Disease Notification Mexico is required when the NOM-035-STPS-2018 psychosocial risk assessment reveals high or very high levels of psychosocial risk in a work area, and workers in that area subsequently present with anxiety disorders, severe depression, or adjustment disorders diagnosed by IMSS or private physicians — the growing body of jurisprudencia from Mexican Tribunales Laborales is increasingly recognizing these conditions as enfermedades de trabajo when a clear causal link to documented workplace risk factors exists.

The notification document is needed when an occupational health surveillance program (programa de vigilancia epidemiológica ocupacional) identifies a cluster of similar health conditions among workers with common workplace exposures — for example, hearing loss among workers in high-noise areas (subject to NOM-011-STPS-2001), musculoskeletal disorders among workers performing repetitive manual tasks, or respiratory conditions among workers exposed to dusts or chemical agents. Cluster identification requires immediate notification and investigation.

An Aviso de Enfermedad Profesional is also required when a worker files a complaint with the IMSS, the STPS Inspección del Trabajo, or a Tribunal Laboral alleging that their health condition is of occupational origin and that the employer failed to report or investigate it — in these situations, having completed the internal notification form and IMSS ST-9 submission prior to the complaint is essential evidence of the employer's good-faith compliance.

For employers subject to periodic occupational health medical examinations (exámenes médicos ocupacionales) under sector-specific NOMs — for example, annual audiometric testing under NOM-011-STPS-2001 for noise-exposed workers — any result showing significant threshold shift or disease progression must trigger completion of an Occupational Disease Notification and IMSS ST-9 filing.

A complete Occupational Disease Notification Mexico must contain the following elements to satisfy LSS Articles 41–48 reporting obligations, LFT Article 504 employer duties, NOM-021-STPS-1994 statistical requirements, and STPS and IMSS inspection documentation standards.

Employer and Workplace Identification: Full legal name (razón social) of the employer, RFC (Registro Federal de Contribuyentes), IMSS Registro Patronal, STPS employer registration number, IMSS risk class (clase de riesgo I–V under LSS Article 73 applicable to the worker's activity), workplace address where exposure occurred, and the specific department or work area where the worker was employed during the exposure period.

Affected Worker Information: Full name, CURP, RFC, NSS (Número de Seguridad Social), job title (puesto), department, seniority in the current position, total years with the company, shift worked during the exposure period, and current IMSS registration status. The SDI (Salario Diario Integrado) must be recorded as it determines the IMSS disability benefit amount under LSS Articles 58–70.

Disease Identification and Classification: The name of the disease or condition as diagnosed, the ICD-10 code (Clasificación Internacional de Enfermedades, 10.ª revisión) if available, the corresponding entry in the IMSS Tabla de Enfermedades de Trabajo (if listed), the date of first symptom onset as reported by the worker, the date of medical diagnosis, the name and medical specialty of the diagnosing physician, and whether the diagnosis was made by IMSS medical services, a company medical service, or a private physician. For conditions not on the Tabla, the notification should document the scientific basis for occupational origin, referencing applicable epidemiological literature and the specific workplace exposure history.

Occupational Exposure History: A detailed account of the worker's occupational exposure to the causal agent — including the specific hazardous substance, physical agent (noise level in dB measured per NOM-011-STPS-2001), ergonomic risk factor, or psychosocial risk factor identified under NOM-035-STPS-2018; the duration of exposure (years and months); the estimated intensity or concentration of exposure; the use and adequacy of personal protective equipment (EPP) during the exposure period; and any prior occupational health monitoring results (audiometry, spirometry, blood or urine analysis) documenting the progression of the condition.

IMSS ST-9 Form Submission Record: Documentation that the IMSS Aviso para Calificar Probable Enfermedad de Trabajo (ST-9 form) was submitted through the IMSS IDSE employer portal within 24 hours of the employer becoming aware of the presumed occupational disease, with the IMSS folio confirmation number. If the IMSS classifies the disease as a riesgo de trabajo, the worker is entitled to all benefits under LSS Articles 58–70 at no cost.

Comisión Mixta de Seguridad e Higiene Investigation Record: Documentation of the Commission's investigation of the occupational disease case — including identification of workplace exposure sources, review of the employer's hazard control measures in the affected work area, assessment of whether applicable NOMs were complied with (e.g., NOM-011-STPS-2001 for noise, NOM-010-STPS-2014 for chemical agents), and the Commission's corrective action recommendations documented in its Acta de Reunión under Articles 509–514 LFT and NOM-019-STPS-2011.

Corrective and Preventive Actions: Specific engineering, administrative, and PPE control measures to be implemented to eliminate or reduce the exposure that caused the disease, with responsible persons, target implementation dates, and verification methods. These measures must be incorporated into the annual Occupational Safety and Health Program (Programa de Seguridad y Salud en el Trabajo) under NOM-030-STPS-2009 and tracked by the Comisión Mixta. Forms-legal.com provides this notification template as a compliance starting point; every occupational disease case should be evaluated by a certified Médico del Trabajo and a Técnico en Seguridad e Higiene registered with the STPS, and documented in a manner consistent with IMSS calificación del riesgo requirements and any applicable sector-specific NOM exposure assessment protocols.