Pat dry with paper towels first to remove the moisture from the outside. Brush halibut with olive oil. Sprinkle with salt, black pepper, garlic powder, and parsley, on top and bottom. Pour lemon juice over the top. Place in refrigerator, on a plate, covered for 1 hour.
Fill smoker with hardwood BBQ pellets. Prepare smoker by placing 2-3 long sheets of aluminum foil along the bottom of the smoker element, underneath the rack, for easier cleanup if desired. Brush grill rack clean.
Set smoker to smoke. Once it starts smoking, set temperature to 200°. Place halibut steaks on grill grate. Smoke for 1.5-2 hours (depending on thickness) or until fish is at 140° F inside.