SANTA FE, N.M. - At a checkpoint on the main road leading into fire-ravaged Los Alamos, officers turning back evacuees and sightseers wore white air-filter masks Saturday as they worked through thick smoke that has settled in the Rio Grande Valley.
The fire that consumed forests and destroyed 260 homes in the town of 11,000 has left a haze over much of northern New Mexico, causing watery eyes and scratchy throats. Its proximity to the Los Alamos National Laboratory has also spread concerns about nuclear weapons stored there, though lab officals say there's no sign of danger.
''Forest fire smoke contains a lot of really nasty compounds,'' said C. Mack Sewell, an epidemiologist in the state Health Department. Among those are carbon monoxide.
For days, the smoke has hung over portions of northern New Mexico as a wildfire burned more than 36,000 acres in the Los Alamos area. A shift in wind direction Friday pushed the smoke into Santa Fe, 35 miles to the southeast. A haze partly obscured the Sangre de Cristo Mountains northeast of the city and an acrid odor lingered in the air.
''You can't go outside. It hurts your throat. We left town the last couple of nights because it was so bad,'' said Terry Mulert, 36, who lives in tiny Cordova, north of Santa Fe, with his wife and 2-year-old son.
Health officials said that the smoke was causing watery eyes, scratchy throats and runny noses across the region, but that the health problems should fade with the smoke. They advised people to remain indoors with windows shut if they have respiratory problems such as asthma, or if they feel eye and throat irritation.
Because of questions about pollution and health hazards from the fire, the U.S. Environmental Protection Agency and the state Environment Department were installing independent air monitoring equipment to measure potential contaminants from the smoke.
The fire also spread through the 43 square miles and 50 technical sites of Los Alamos National Laboratory, though officials there said no radioactive materials were burned. A lab spokesman said air monitoring has detected no elevated levels of radioactivity in the area.
The lab, which is part of the federal nuclear weapons complex, permanently operates an air monitoring network on its property and nearby areas. Once the fire began, it also placed air sampling devices in outlying towns - some up to 40 miles away - to test the smoke plume.
''There are a lot of rumors floating around. This is to give that extra comfort level to the public to rest assured their health is not being impacted by radioactivity,'' said Doug Stavert, the lab's air quality group leader.
The lab has maintained that its main supplies of radioactive materials and high explosives are safely protected from the fire in reinforced buildings or concrete bunkers.
But questions remain about buried dumps on lab property - some dating to early atomic bomb work in the 1940s - that contain millions of cubic feet of wastes contaminated with plutonium, uranium and tritium.
Because of the continuing fire threat, the lab hasn't been able to survey the waste sites to determine which ones were burnt, Stavert said.