Growing industry cashes in on good intentions, but at a cost, critics say

Rapid growth in the multi-billion dollar volunteer tourism industry has prompted calls for tighter controls with concerns over exposing vulnerable communities to unskilled foreign labor and dodgy operators exploiting foreigners for profit.

Voluntourism, which allows socially-conscious holiday-makers to pay thousands of dollars to work in poor communities across South America, Asia and Africa, has become a boom sector of the global travel industry.

Estimates of its size vary widely. Nancy Gard McGehee, an expert on sustainable tourism at the U.S. university Virginia Tech, says as many as 10 million volunteers a year are spending up to $2 billion on the opportunity to travel with a purpose.