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The installation of filters on equipment will have the beneficial effect of limiting the exposure of personnel to DPM. The installation and use of these filters, however, must not create safety hazards with the operation of the machine. Other Best Practices have discussed the hazard of hot surfaces from the addition of filter piping and housings and the potential for uncontrolled regeneration (fire) in a ceramic filter on nonpermissible equipment. This Best Practice discuss the potential hazards of installing filters in a manner that limits the operator's field of view.

Some filter installations add large filter housings near the engine compartment. These large units allow longer filter maintenance intervals and reduce the machine's downtime. The large filter housings can, however, block the operators view to the rear of the machine. Since these machines usually have limited visibility, any additional obstructions can greatly increase the hazard of collisions with other vehicles or personnel. Reference EIMCO 915E Visibility Report and NIOSH Software: Visibility.

Consult with the equipment manufacturer, filter manufacturer, and MSHA concerning the visibility requirements at your mine before purchasing new equipment. Any retrofits of equipment to add DPF's should consider the effect the installation will have on operator visibility. Contact your local MSHA office or Dennis Ferlich at MSHA's Approval and Certification Center, 304-547-2058 or mail to:, for more information.