What is PREXOR?
PREXOR is the Chilean standard for organizing surveillance of work-related hearing loss. The version approved by the Ministry of Health in 2013 integrates environmental and health surveillance. Its implementation must be coordinated with Supreme Decree 594 and the current technical procedures of the Public Health Institute.
Workplace noise requires ongoing management. A single measurement or the distribution of earplugs alone does not describe how exposure is controlled. The program must identify which tasks generate noise, who is exposed, and what decisions are being made. This continuity helps detect changes that might otherwise go unnoticed between assessments.
Action criteria and limits
The protocol uses a fifty percent action dose, equivalent to 82 dB(A) for eight effective hours, and a peak criterion of 135 dB(C) for impulsive noise. These values trigger preventive actions according to the protocol; they should not be presented as universal maximum limits nor applied without adjustment to any workday duration.
The comparison requires correctly identifying the measured indicator. An instantaneous noise level next to a machine is not the same as cumulative personal exposure. Noise dosimetry can help characterize variable jobs, but it requires planning and competent interpretation. Before concluding that an exposure is acceptable, the duration, tasks, and conditions represented by the measurement must be reviewed.
Representative assessment of the exposure
The Public Health Institute has an updated assessment protocol for 2025. Planning should characterize positions and activities, select the appropriate strategy, and document the observed conditions. The quality of the result depends on both the instrument and its monitoring, as well as on the assessment period reasonably representing the exposure being studied.
It is advisable to record changes in production, tools, materials, and maintenance. An assessment during a day of reduced activity may not reflect peak demand periods. It is also important to identify individuals who work in different areas and tasks. Grouping them solely by their administrative position can mask significant differences in the amount of time they spend near noise sources.
Workplace control measures
Management should consider solutions for noise sources and transmission, as well as organizational measures and personal protective equipment where appropriate. Reducing impacts, improving maintenance, or revising the design may be more effective than relying solely on individual behavior. The specific solution requires technical evaluation to ensure that changes do not introduce other hazards or interfere with operations.
Once implemented, its effect must be verified. Simply recording the installation of a cover does not automatically demonstrate that exposure has been sufficiently reduced. It is advisable to check its performance during relevant tasks and establish how it will be maintained. Measures can lose effectiveness due to wear and tear, modifications, or openings that are eventually standardized to facilitate work.
Selection and use of hearing protection
Hearing protection requires selection appropriate to the exposure and conditions of use. The Public Health Institute’s guide also covers purchase, training, maintenance, and replacement. The declared attenuation level does not necessarily correspond to the level achieved by each individual throughout their workday, especially if there are fitting problems or intermittent use.
Compatibility with other equipment and communication requirements must be verified. An uncomfortable or unsuitable protector may be repeatedly removed, reducing effective protection. Hands-on training should enable users to fit and maintain it correctly. The program also needs a clear response when the equipment deteriorates or ceases to meet the task requirements.
Hearing health monitoring
Health surveillance is organized according to exposure and protocol criteria, with assessments performed and interpreted by qualified personnel. Its purpose is to detect abnormalities and guide interventions. Occupational hearing loss is not determined through informal assessments or by the subjective impression that a person hears worse at the end of the workday.
Clinical results must be kept confidential. For preventive management, it is important to receive the necessary conclusions regarding exposure, measures, and follow-up, without indiscriminately disseminating individual health information. Hearing impairment should prompt a review of work practices and protective measures; repeating examinations without correcting exposure leaves the process incomplete.
Practical example
In a hypothetical scenario, a workshop incorporates a second impact operation while maintaining the same hearing protection. A review of the program identifies that the previous assessment no longer represents the entire activity. The current exposure is characterized, and changes at the source and in the organization are studied, with technical support to select appropriate measures.
The company verifies its effectiveness, updates instructions, and coordinates appropriate monitoring. It also establishes procedures for reviewing future tool purchases to consider noise from the outset. The learning process involves linking production changes to the preventive program, ensuring that measurements and protection measures are not tied to outdated working conditions.
Evidence and monitoring of the program
A traceable program maintains the characterization, reports, control decisions, and subsequent checks. It also identifies those responsible for maintenance, training, and health coordination. It is useful to link each action to the exposure it aims to reduce, so that monitoring is not limited to simply counting activities performed without evaluating their results.
Timeframes and frequencies should be taken from the protocol and relevant guidelines for the case. Reviews should be brought forward when relevant conditions change. PREXOR provides a framework for maintaining this connection between assessment, intervention, and monitoring, within a management approach that aims to prevent hearing damage before it becomes irreversible.
