Indigenous groups are threatened as Peru gears up for an energy boom.

POROTOBANGO, PERU

Raised in palm huts deep in the Peruvian Amazon, Gregorio Torres never imagined that below his home was something called natural gas.

Now his Machiguengua Indian settlement in this rain-forest river clearing has solar-powered radio gifted by an international oil company, corrugated tin roofs, T-shirts with company logos, and a shelf of Western medicine.

But this incipient natural-gas boom is bringing new worries, too.