No one is quite certain what goes into LaCroix (“La-croy”), the carbonated water that’s become a popular alternative to soft drinks. The zero-calorie beverage comes in several distinctive fruit flavors that the drink’s parent company, National Beverage, has described as being derived from “natural essence oils.” That highly secretive process is believed to be the result of heating fruits and vegetables, then making a concentrate out of the vapor.

To try and crack the mystery, Consumer Reports recently approached officials in Massachusetts with a public records request for documentation relating to LaCroix. Massachusetts is one of the few states requiring manufacturers of carbonated water to obtain a permit and submit water quality tests to sell their product.

The verdict? Consumer Reports still isn’t quite sure what goes into LaCroix. But it might be technically against state regulations to sell it in Massachusetts. That’s because the state has no records on file for the mystery refreshment.

The Massachusetts Department of Public Health could not find a permit for LaCroix, and there were no water quality test results on hand, either. Without those documents, the drink should technically not be for sale in the state. After noticing the oversight, Massachusetts sent a request to National Beverage for the necessary information. If the company fails to comply, the state could end up fining them or banning the sale of the drink. A spokesperson for National Beverage told Consumer Reports the company intended to comply with the request.

Why does the state need any information at all? Thanks to some bureaucratic quibbling, carbonated water products are treated differently than bottled water by regulatory agencies. The Food and Drug Administration considers carbonated beverages like seltzer and flavored sparkling water to fall under the heading of soft drinks. While the FDA mandates certain manufacturing standards for those drinks, it doesn’t apply the same rules as it does for bottled water, which is expected to adhere to strict rules about contaminants and quality testing. That leaves certain states like Massachusetts to conduct their own quality assessments.

There’s no guarantee that such testing will divulge LaCroix’s secret to their flavoring process, which is likely to remain a mystery.

[h/t Food & Wine]