Occupational exposure to intermediate frequency and extremely low frequency magnetic fields among personnel working near electronic article surveillance systems

Abstract

Cashiers are potentially exposed to intermediate frequency (IF) magnetic fields at their workplaces because of the electronic article surveillance (EAS) systems used in stores to protect merchandise against theft. This study aimed at investigating occupational exposure of cashiers to IF magnetic fields in Finnish stores. Exposure to extremely low frequency (ELF) magnetic fields was also evaluated because cashiers work near various devices operating with 50 Hz electric power. The peak magnetic flux density was measured for IF magnetic fields, and was found to vary from 0.2 to 4 µT at the cashier's seat. ELF magnetic fields from 0.03 to 4.5 µT were found at the cashier's seat. These values are much lower than exposure limits. However, according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) occupational reference levels for IF magnetic fields (141 µT for the peak field) were exceeded in some cases (maximum 189 µT) for short periods of time when cashiers walked through the EAS gates. As the ICNIRP reference levels do not define any minimum time for exposure, additional investigations are recommended to determine compliance with basic restrictions. Even if the basic restrictions are not exceeded, persons working near EAS devices represent an exceptional group of workers with respect to exposure to electromagnetic fields. This group could serve as a basis for epidemiological studies addressing possible health effects of IF magnetic fields. Compliance with the reference levels for IF fields was evaluated using both broadband measurement of peak fields and the ICNIRP summation rule for multiple frequencies. The latter was generally more conservative, and the difference between the two methods was large (>10-fold) for EAS systems using a 58 kHz signal with complex waveform. This indicates that the ICNIRP multiple frequency rule can be unnecessarily conservative when measuring complex waveforms.

AI evidence extraction

Main findings

At the cashier’s seat, IF peak magnetic flux density ranged from 0.2 to 4 µT and ELF magnetic fields ranged from 0.03 to 4.5 µT, described as much lower than exposure limits. ICNIRP occupational reference levels for IF peak fields (141 µT) were exceeded in some cases for short periods when cashiers walked through EAS gates (maximum 189 µT). The ICNIRP multiple-frequency summation rule was generally more conservative than broadband peak measurements, with >10-fold differences for EAS systems using a 58 kHz complex waveform.

Outcomes measured

• Intermediate frequency (IF) peak magnetic flux density at cashier seat
• Extremely low frequency (ELF, 50 Hz) magnetic flux density at cashier seat
• Peak IF magnetic flux density when walking through EAS gates
• Compliance with ICNIRP occupational reference levels for IF magnetic fields
• Comparison of compliance assessment methods (broadband peak vs ICNIRP multiple-frequency summation rule)

Limitations

• Sample size not reported in the abstract
• Exposure duration for gate transits not quantified
• Health outcomes were not assessed (exposure/compliance-focused study)

Suggested hubs

• occupational-exposure (0.95)
  Assesses workplace magnetic-field exposure among cashiers near EAS systems.
• who-icnirp (0.7)
  Evaluates compliance with ICNIRP occupational reference levels and discusses implications of ICNIRP summation rule.

{
    "study_type": "exposure_assessment",
    "exposure": {
        "band": "IF/ELF",
        "source": "electronic article surveillance (EAS) systems; workplace devices using 50 Hz power",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "short periods when walking through EAS gates (time not quantified)"
    },
    "population": "Cashiers/personnel working near EAS systems in Finnish stores",
    "sample_size": null,
    "outcomes": [
        "Intermediate frequency (IF) peak magnetic flux density at cashier seat",
        "Extremely low frequency (ELF, 50 Hz) magnetic flux density at cashier seat",
        "Peak IF magnetic flux density when walking through EAS gates",
        "Compliance with ICNIRP occupational reference levels for IF magnetic fields",
        "Comparison of compliance assessment methods (broadband peak vs ICNIRP multiple-frequency summation rule)"
    ],
    "main_findings": "At the cashier’s seat, IF peak magnetic flux density ranged from 0.2 to 4 µT and ELF magnetic fields ranged from 0.03 to 4.5 µT, described as much lower than exposure limits. ICNIRP occupational reference levels for IF peak fields (141 µT) were exceeded in some cases for short periods when cashiers walked through EAS gates (maximum 189 µT). The ICNIRP multiple-frequency summation rule was generally more conservative than broadband peak measurements, with >10-fold differences for EAS systems using a 58 kHz complex waveform.",
    "effect_direction": "unclear",
    "limitations": [
        "Sample size not reported in the abstract",
        "Exposure duration for gate transits not quantified",
        "Health outcomes were not assessed (exposure/compliance-focused study)"
    ],
    "evidence_strength": "insufficient",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "occupational exposure",
        "cashiers",
        "electronic article surveillance",
        "EAS",
        "intermediate frequency",
        "IF magnetic fields",
        "extremely low frequency",
        "ELF",
        "50 Hz",
        "ICNIRP",
        "reference levels",
        "58 kHz",
        "complex waveform",
        "multiple frequency summation rule"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.9499999999999999555910790149937383830547332763671875,
            "reason": "Assesses workplace magnetic-field exposure among cashiers near EAS systems."
        },
        {
            "slug": "who-icnirp",
            "weight": 0.6999999999999999555910790149937383830547332763671875,
            "reason": "Evaluates compliance with ICNIRP occupational reference levels and discusses implications of ICNIRP summation rule."
        }
    ]
}

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