Filling or handling plastic or other non-conducting containers can still be hazardous when the flammable liquid is conductive. The splashing (filling) and turbulence of the liquid in the container can cause a static electric charge to build up in the liquid or on conductive parts of the container that are not adequately grounded. A spark above the MIE of the vapor/air mixture in its flammable range (an incendive discharge) can originate from the liquid or the container.
For portable tanks, intermediate bulk containers, and non-bulk containers, NFPA advises grounding any metal parts on the container (and nearby conductive surfaces that the container may contact) and filling the container FROM THE BOTTOM THROUGH A LONG, GROUNDED METAL PIPE. This procedure will reduce the static charge produced and enable the generated charge to relax (dissipate) through the metal pipe.
Use the smallest container for the job. The risk of fire from static electricity increases with the volume of the container and the volatility of the liquid being used.
When filling non-conducting portable containers, NFPA recommends that a grounded dip pipe or grounded wire be in the liquid in the container while it is being filled. The filling rate should be MINIMIZED, especially if there is an in-line filter.
Any metal parts of the container and metal funnel, if one is used, should also be grounded. When filling containers with low-conductivity liquids (i.e., ones with a conductivity LESS THAN 50 picoSiemens, pS), we should keep the grounded dip rod in the liquid for 30 SECONDS after the filling.