The Environmental Protection Agency and Exxon Mobil will test indoor air, cropland soils and residential wells downstream of a Yellowstone River oil spill for contamination.

Residents have raised concerns about hazards from the tens of thousands of gallons of crude that poured into the watercourse.

EPA and local officials say they do not expect to find significant health dangers but were acting as a precaution. Some residents in oil-stained areas have complained of nausea, dizziness and shortness of breath that have lingered for days.

An estimated 42,000 gallons have fouled areas along the scenic Yellowstone since Friday after a 12-inch pipeline operated by Exxon Mobil broke near the town of Laurel.

EPA on-scene coordinator Steve Merritt said contractors will have the results of air samples in about a week.

Assocaited Press