MAGDALENA, N.M. (AP) – A 3-week-old wildfire continues to produce smoke and haze over west-central New Mexico as it has grown to nearly 40 square miles with firefighters igniting some areas and the fire growing elsewhere on its own.

The so-called “North Fire” is burning in a sparsely populated areas of grass and timber in the San Mateo Mountains around 25 miles southwest of Magdalena.

Officials say the lightning-caused fire that started May 21 on the Cibola National Forest and National Grasslands is 30 percent contained.

Surrounding communities are experiencing drifting smoke and haze in the afternoon and evenings, and the New Mexico Air Quality Bureau has placed a smoke monitor in the area.

Approximately 140 personnel are assigned to the fire.