Montana officials have started issuing permits to an Exxon Mobil subsidiary to ship about 300 loads of oversized oil refinery equipment over interstates 90 and 15 to the northern border.

Duane Williams of the state Department of Transportation said Wednesday the agency has so far issued permits for six loads to travel from the Idaho-Montana line to Alberta, Canada.

The modules are smaller versions of the so-called megaloads that Imperial Oil had proposed shipping across scenic two-lane highways in Idaho and Montana. A judge has temporarily blocked the loads from that original route while he considers a legal challenge.

Imperial Oil officials have said the company applied to transport all of the modules along the interstate route rather than jeopardize plans to have the equipment in place by late 2012.

Associated Press