EMF exposure limits in the USA


The USA has no Federal exposure limits for ELF EMFs.

The American Conference of Governmental Industrial Hygienists (ACGIH) publish recommended occupational exposure limits, but these have no legal force.


We are aware of the following six States which have exposure limits, mostly applying specifically to power lines:

State Area where limits applies Field Limit
Florida Edge of right-of-way Electric 2 kV m-1
230 kV lines Magnetic 15 μT
500 kV lines 20 μT
Anywhere 69-230 kV lines Electric 8 kV m-1
500 kV lines 10 kV m-1
Minnesota Anywhere Electric 8 kV m-1
Montana Edge of right-of-way May be waved by landowner Electric 1 kV m-1
Road crossings Electric 7 kV m-1
New Jersey Edge of right-of-way Electric 3 kV m-1
New York Edge of right-of-way Electric 1.6 kV m-1
Magnetic 20 μT
Public road crossings Electric 7 kV m-1
Private road crossings Electric 11 kV m-1
Anywhere Electric 11.8 kV m-1
Oregon Accessible or inhabited areas Electric 9 kV m-1


In addition, the following States have versions of “prudent avoidance” (similar to what tend to be called "precautionary policies" in Europe) applied to new power lines:

  • California: requirement to include EMF reduction measures in new power-line projects up to 5% of project cost, plus specific provisions for schools
  • Colorado, Maryland: prudent avoidance decided through a specific siting case which set precedent and was subsequently applied to all new siting applications
  • New Jersey: more of a practice than a policy
  • Connecticut, Hawaii: formal policy
  • Ohio: requires utilities to “prudently address” EMF issues
  • Pennsylvania: staff handling siting applications expect evidence of prudent avoidance but has never been set down as formal policy

This information is based on our best understanding but we welcome corrections or additions - please contact us if you have better information.

μT or mG?

This site gives all magnetic fields in units of microteslas (μT).  In the USA, the unit milligauss is often used instead.  To convert from μT to mG, multiply by 10.  To convert from milliteslas (mT) to gauss, multiply by 10.  Or use this conversion chart.