Human response to very low-frequency electromagnetic energy
Frey AH · 1963
Workers on the VLF transmitter tower experienced strong electric shocks and reflex withdrawal that could cause fatal falls, with fields up to 989,000 volts per meter at the ladder top.
Plain English Summary
Researchers measured alternating electric fields at a VLF transmitter site operating at 14.7 kc with 1100 kw radiated power. At the tower top center the field was 30,000 volts per meter and tingling occurred on bare metal and sometimes on painted metal. At the ladder top the field reached 989,000 volts per meter, producing strong shocks comparable to a 115 volts ac line and causing reflex withdrawal without muscle freezing.
Why This Matters
An aluminum hard hat drew a small spark when touched to bare metal at the 470-foot level, but the palm of the hand felt no unusual sensation at the same spot. The grill floor ten feet below the roof produced no noticeable sensations from radiation. Workers could not use bare hands on the top five feet of the ladder and climbed using only feet and safety belt.
Finding
At the top of the ladder, which protrudes about two feet above the roof, the ac field was measured as 989,000 volts per meter. All metal parts, painted or unpainted, produced a strong and unpleasant electric shock when touched — comparable to that which occurs when one touches a live power line of 115 volts ac.
In their words
“At the top of the ladder, which protrudes about two feet above the roof, the ac field was measured as 989,000 volts per meter. All metal parts, painted or unpainted, produced a strong and unpleasant electric shock when touched — comparable to that which occurs when one touches a live power line of 115 volts ac.”
Exposure Details
- Electric Field
- 989,000 V/m
Exposure Context
This study used 989,000 V/m for electric fields:
- 3.3Mx above the Building Biology guideline of 0.3 V/m
Building Biology guidelines are practitioner-based limits from real-world assessments. BioInitiative Report recommendations are based on peer-reviewed science. Check Your Exposure to compare your own measurements.
Show BibTeX
@article{human_response_to_very_low_frequency_electromagnetic_energy_g6646,
author = {Frey AH},
title = {Human response to very low-frequency electromagnetic energy},
year = {1963},
}