Workplace lighting levels in Mexico: the NOM-025 lux table

A corporate lighting spec written in foot-candles and averaged over a whole bay does not answer the question an inspector asks at a single workstation. Mexico's workplace lighting levels come from NOM-025-STPS-2008, a mandatory standard (NOM, Norma Oficial Mexicana) issued by the STPS, Mexico's federal labor ministry, and they are minimums measured on the work plane for each visual task. For plants in San Luis Potosí, SIISA runs the lighting survey with an allied laboratory as part of its STPS compliance consulting.

What lux levels does Mexico require by task?

NOM-025-STPS-2008 was published in the DOF (Mexico's Official Gazette) on December 30, 2008, and replaced the 1999 version. PLATIICA, the Ministry of Economy's catalog of standards, lists it as in force, with a systematic review dated February 27, 2024 that ended in "confirmation". A 2015 amendment removed one paragraph of the measurement appendix and one method from the reference guide; Table 1 did not change. The standard applies to every work center in Mexico (section 2).

Table 1 sets minimums that must reach the work plane, the horizontal, vertical or tilted surface where the person works (sections 4.14 and 7). The foot-candle column is a unit conversion for orientation only.

On a Mexican line the minimum follows the task at each station, so one bay can carry several different targets.

Mexican lux levels and the US foot-candle tables

One foot-candle is one lumen per square foot, about 10.76 lux. In the US, the best-known OSHA lighting table (OSHA is the Occupational Safety and Health Administration) sits in the construction rules, 29 CFR 1926.56. Its Table D-3 asks for 30 foot-candles in first aid stations, infirmaries and offices, about 323 lux; 10 in general construction plants and shops, about 108 lux; and 5 in indoor warehouses, corridors and exitways, about 54 lux.

Some numbers look close, but NOM-025 works differently. It assigns a minimum to each visual task, it is checked on the work plane where that task happens, and it requires a documented survey with a formal report. If your corporate spec averages illuminance over a room, a bay can pass on average while one inspection bench falls short of Table 1. Use the conversion to read your corporate spec, and use Table 1 to show compliance in Mexico.

How workplace lighting levels are measured in Mexico

The survey has two parts. The recognition (reconocimiento, chapter 8) is a walk-through that records fixtures and lamp wattage, machinery, surface colors, tasks by Table 1 row, stations needing localized lighting and worker reports (8.2). The evaluation (chapter 9 and Appendix A) takes place during a workday under normal operating conditions (9.1.2):

• Discharge lamps, fluorescents included, run 20 minutes before readings; new installations with those lamps need 100 operating hours first (A.2.1).
• Where daylight affects the area, each point gets three readings across the shift: near the first hour, mid-shift and the last hour (A.2.2).
• Each workstation gets at least one reading per work plane, with the meter as close to it as possible and without casting a shadow on it (A.2.4).
• Reflectance is checked too: glare exists when it exceeds 60% on walls or 50% on the work plane (Table 2).

The report (section 12.1) has eleven required items, including a layout with the measurement points, results with their uncertainty, the time of each reading, the maintenance program, control measures with an implementation schedule and the name and signature of the person responsible. Ask your vendor for all eleven items, because the inspector reviews the report against that list.

How often must a lighting survey be repeated?

NOM-025 sets no fixed interval. The results report is kept "while the conditions that gave rise to that result are maintained" (5.4), and section 13.3 declares it valid on the same terms. If someone quotes you a two-year cycle, it comes from that same section 13.3, where two years is the validity of a favorable verification report (dictamen) from a verification unit (unidad de verificación). That is an accredited and approved private inspection body the employer may choose to hire.

What the standard does tie to change: the recognition is updated as fixtures or lighting conditions change (8.2), and a new evaluation follows any control measure (10.4). In a plant: a fixture retrofit, a new layout, a line move, a more demanding task at a station or a corrected area. If your global EHS calendar runs a survey every two years, keep it as a company rule and add the change triggers Mexico requires.

Can your in-house EHS team run the survey?

Yes, if it follows the method. Section 13.1 makes hiring a verification unit or a testing laboratory, accredited and approved, an option for the employer. A laboratory may only evaluate chapters 8 and 9, recognition and evaluation (13.4); a verification unit issues the dictamen (13.5) and may not provide diagnosis, programs or training to the company it evaluates (14.1.3).

The instrument has no such flexibility. The light meter (luxómetro) needs cosine correction, color correction within ±5% of the photopic response and ±5% accuracy (A.3.1). It is checked before and after each evaluation (A.3.2), and the report includes a copy of its calibration document issued by an accredited and approved laboratory (12.1 g). An in-house survey holds up when the meter paperwork and the eleven report items are complete.

SIISA runs lighting and noise studies with an allied laboratory, and both can be quoted together for the same plant.

Eye exams and emergency lighting under NOM-025

Section 5.9 requires yearly visual acuity, visual field (campimetry) and color perception exams for workers in areas with special lighting. The standard defines special lighting as what an activity with high visual demand requires, above 1,000 lux or below 100 lux (4.8). In conformity assessment the duty applies to high-risk zones with high visual demand, and the physician may be in-house or external (14.1.2). Our guide to pre-employment medical exams in Mexico covers which other exams Mexican standards require.

Emergency electric lighting goes where losing artificial light creates a risk for the visual task, and on evacuation routes that need it (5.11). Table 1 lists emergency lighting at 50 lux, the maintenance program covers it (5.10), and on the walk-through the inspector checks that it exists and works.

When an area reads low: controls, records and fines

Section 10.2 lists the fixes: maintain the fixtures, change the lighting system or its layout, or add supplementary or localized lighting while avoiding glare, choosing a suitable visual background, not blocking the light and avoiding abrupt changes in illuminance. Glare from too much light also needs controls (10.1). The measures go into a program (10.3), a new evaluation confirms them (10.4), and the report keeps results until the area complies (12.1 k). A retrofit counts once a new reading shows the area meets Table 1. Workers must also be told about the risks of poor lighting and glare (5.8).

The same assessment procedure applies to STPS inspections and to verification unit visits (14.2), and Table 1 compliance is checked physically on a walk-through (5.2). Failing to observe safety and health standards carries fines of 250 to 5,000 UMA, Mexico's daily unit for fines, per affected worker: MXN 29,327.50 to MXN 586,550 with the 2026 UMA of MXN 117.31 (Federal Labor Law, LFT, arts. 992 and 994, section V). Our guide to STPS fines in Mexico shows how those amounts add up, and the register of STPS standards that apply to your plant places NOM-025 among the rest.