A group of GOP House energy leaders advised Health and Human Services Secretary Kathleen Sebelius to exercise caution in a possible study on the health impacts of natural-gas drilling.

The Centers for Disease Control and Prevention is considering examining a potential link between hydraulic fracturing, or fracking, and drinking water contamination.

The lawmakers sent a letter to Sebelius Friday stating that such a study could stymie job growth if not properly executed. They expressed concern in the letter that naturally occurring substances in groundwater could be improperly labeled as contaminants.