Stubborn forest fires in western Labrador have forced police to again shut down the main highway, as smoke from fires in the area and Quebec compromise air quality again.

The Trans-Labrador Highway near Wabush — the mining town that was temporarily evacuated last weekend — was closed late Thursday night, with the Royal Newfoundland Constabulary saying it was too dangerous to provide escorts for vehicles trying to reach communities in Labrador's interior.

The highway shutdown has meant that even emergency vehicles cannot get through, including a massive Oshkosh firefighting engine that the Iron Ore Company of Canada was delivering to the scene. There are only six vehicles of its size in Canada.

Police said conditions were too unpredictable to let anyone through.

Power and telecommunication service was also lost in parts of Labrador late Friday afternoon. Bell Aliant said a fibre break similar to one last week was caused by the forest fires in the area.

No long distance is available in Labrador West, but local landline and digital cell service were not affected.

Internet service was also down in Happy Valley-Goose Bay, but landline and digital cell services were OK.

911 phone services are down in Labrador West. RNC advise residents to call 709-944-7602 to get in contact with police if needed.

In case of an emergency only, cell phone users can call 709-280-9011 or 709-280-2841.

Wabush remained in a state of emergency Friday as officials warned residents to be prepared for another evacuation call.

Water bombers were grounded for most of Thursday because smoke filled the air. Much of the smoke this time had blown from fires burning in Quebec.

Eric Earle is a provincial fire duty officer with the Department of Natural Resources.

"There's really nothing we can do to prevent the smoke from Quebec. We are focused on protecting these two towns (Labrador City and Wabush) from the fire," Earle said.

He said ground crews are accessing the fire through the Trans-Labrador Highway to battle hotspots, but that it's difficult to pinpoint the exact location of the flareups.

Labrador Grenfell Health, the regional health authority, issued an air quality advisory, and told residents they should stay indoors with their windows closed. The authority also urged residents to stay hydrated.

Meanwhile, an air quality warning was extended Friday morning to much of Newfoundland. The joint warning from Environment Canada and Newfoundland and Labrador's Department of Environment and Conservation covered an area that stretched from St. Anthony to Burgeo.

As far east as St. John's, skies were notably hazier than normal.

Conservation officer Chuck Porter said the Quebec fires are not an imminent threat.

"There's a lot of water between us and them, and massive water bodies," Porter said.

"It would take such an amount of time that the chances of it not raining [in that time are] almost impossible."