substantial evidence that some of the fires have been caused by people who cross our border illegally." one immigration activist called mccain's comment baseless and unsubstantiated. authorities are blaming a campfire for the largest of the state's fires. mccain's office today said senators comments were about other fires in the state. we go east from arizona to texas. unusual story of government, energy business and environmentalists all being on the same page. at least partially. senior national correspondent john roberts explains. >> the key to the energy boom. hydraulic fracturing where fluid is pumped in the gas well, trapping the rock and releasing trapped gas. 98% is water and sand. but the fluid contains toxic chemicals the industry has been reluctant to reveal. last october, don and carol johnson beef cattle drank spilled fracturing fluid. the herd had to be quarantineed. they had no idea what was in