More than 10 million bottles of water left to rot on a Puerto Rican airport tarmac were deemed “excess” supplies that federal officials decided the island didn’t need while recovering from Hurricane Maria, FEMA said on Thursday.

The agency said the close to 20,000 pallets of drinking water that could contain as many as 12 million bottles were considered extra in February.

“We had provided [water] to every volunteer agency that had a warehouse, every entity… a lot of municipalities had excess water,” said Justo Hernandez, operational coordination division director for FEMA, in a conference call with reporters Thursday.

The agency said it also stopped distributing water at that time because “commerce was coming back” to Puerto Rico and officials “didn’t want to injure the economy more than it already was.”

But in late April, the local Puerto Rican General Services Administration requested the water bottles from FEMA and began giving them out in May. The local agency handed out about 700 pallets before receiving two complaints that the water smelled and tasted foul.

But Hernandez insisted most of the water is drinkable.

“I can not assure you that all the water is good,” he said. “Some spoiled.”

An investigation was opened two days ago into why the water was requested after it was labeled as excess by FEMA, Hernandez said.

The investigation will also assess how the remaining water will be disposed and whether any of it can still be used.

The water was originally moved from containers to a runway at the José Aponte de la Torre Airport in Ceiba in January as a cost-saving measure, Marty Bahamonde, director of disaster operations for FEMA’s Office of External Affairs, told CBS News.

Prior to the move, the agency had been storing water in 1,100 containers on the island at a cost of about $300,000 a day, Bahamonde said.

“FEMA put that water out on that airstrip for the purpose of getting it out of containers, so that there would be no cost to us and no cost to the taxpayer,” he said. “In hindsight, it saved us tens of millions of dollars.”

The agency didn’t ship the bottles back to the US for use in future disasters when they were no longer needed because that was “cost prohibitive,” Bahamonde said.

“Anytime we waste water, that’s something we try absolutely not to do,” he said. “We will never apologize for erring on the side of having too much of a commodity in a place, because that’s what we’re supposed to do.”