The Advanced Photon Source
a U.S. Department of Energy Office of Science User Facility

Experiment Hazard Class 9 – Electric and Magnetic Fields


This hazard classification applies to all experiments involving magnets, magnetic fields, and electric fields.  Other hazard classifications such as electrical safety and their associated hazard controls may also apply to experiments in this hazard class.

Experiment Category
Experiments involving this hazard class are categorized as medium risk experiments unless other hazard classes apply.
Experiment Hazard Control Verification Statements

Controls – Persons with cardiac pacemakers or other medical devices that may be affected by magnetic or electric fields are prohibited from entering areas where the steady state magnetic field exceeds 0.5 mT (5G) or the steady state electric field exceeds 1000 V/m.  Barricades/warning tape should be posted as appropriate.

Procedural Controls – Safe work procedures to handle hazards should be developed.  Shielding should be used whenever possible.  Personnel exposure should be limited as hand tools can become missiles in a sufficiently strong magnetic gradient.  Pinch hazards can be present as well.  Only non-ferromagnetic tools should be used in areas where the magnetic field may exceed 3 mT.  If the electric field strength will be greater than 5,000 V/m, eliminate ungrounded objects and/or use insulated gloves when ungrounded objects must be handled.  Consult with ESQ-IH regarding safe work practices for work in electric fields that exceed 15,000 V/m.

Design Reviews and Equipment Inspections – The Medical Department must evaluate and counsel all employees with cardiac pacemakers or other medical implants prior to work with magnetic or electric fields.

Signs and Labeling – Post areas where magnetic fields exceed 0.5 mt (5G) or electric fields exceed 1,000 V/M.  Signs should include the following: "Caution! DO NOT ENTER! Electromagnetic fields could be harmful to persons wearing pacemakers or other medical electronic implants."  Signs are available through the Divisional ESH Coordinators.

Personal Protective Equipment – Electric fields that exceed 15,000 V/m require the use of protective devices (suits, gloves, and insulation).

Hazard Control Assistance

Consultation is available through the Divisional ESH Coordinators and ESQ-IH.  Contact the local floor coordinator for assistance in setting up a consultation.

Experiment Authorization

Unless otherwise noted in the approved experiment safety plan, the PSC Deputy Associate Laboratory Director of Operations delegates the authority to authorize an experiment in this hazard class to a member of the APS Experiment Safety Review Board and resident beamline personnel having the authority to authorize experiments as listed in the ESAF system.  Approval by both the host beamline and APS Experiment Safety Review Board are mandatory prerequisites for experiment authorization.

Hazard Control Verification

The PSC Deputy Associate Laboratory Director of Operations delegates responsibility for verifying that required controls are in place to the experiment On-Site Spokesperson and Beamline Management.


LMS-PROC-234: Electric and Magnetic Fields 4/16/2020 (Internal link)

Contact the APS User Safety Program with any questions or if the internal links are not working properly.

Reviewed: May 6, 2020