Radon is a naturally occurring toxic gas that comes up from the earth and enters buildings through cracks in the foundation, tiny leaks in the walls, floors, and even though the water.
How does it get inside buildings?

Is New Mexico known for having radon?
Albuquerque, Santa Fe, and surrounding areas are known to have elevated levels of radon. See this chart from the EPA:

Why should we be concerned about radon?

What can be done to reduce radon?
Test where you and your loved ones spend the most time indoors! It is easy to test for radon and if the level is high, mitigation is a practical method to divert gases from entering homes and offices.

For more information from the Environmental Protection Agency: