Limits in the USA

flag of 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.

The International Commission on Electromagnetic Safety (ICES)/IEEE publish exposure limits, and they are an American-based organisation so that their limits are sometimes seen as American, but again, they do not have formal sttus in any US jurisdiction that we are aware of.


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

StateArea where limits appliesFieldLimit
FloridaEdge of right-of-way Electric2 kV m-1
230 kV linesMagnetic15 μT
500 kV lines20 μT
Anywhere69-230 kV linesElectric8 kV m-1
500 kV lines10 kV m-1
MinnesotaAnywhereElectric8 kV m-1
MontanaEdge of right-of-wayMay be waved by landownerElectric1 kV m-1
Road crossingsElectric7 kV m-1
New JerseyEdge of right-of-wayElectric3 kV m-1
New YorkEdge of right-of-wayElectric1.6 kV m-1
Magnetic20 μT
Public road crossingsElectric7 kV m-1
Private road crossingsElectric11 kV m-1
AnywhereElectric11.8 kV m-1
OregonAccessible or inhabited areasElectric9 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.