A preliminary report released by two federal agencies confirmed that when the state accidentally dropped 125, 1.3-ton concrete slabs onto a swath of coral reef off South Maui last year, it damaged a living habitat for myriad fish and other aquatic life-forms, the Maui News reported.

The decades-old Keawakapu artificial reef is in 60 to 120 feet of water about a half mile out from the border of Kīhei and Wailea. On Dec. 2, the state Department of Land and Natural Resources was increasing the size of the reef by dropping 1,400 slabs onto what experts apparently thought was sand and areas of algae, according to a preliminary report issued last week by the U.S. Fish & Wildlife Service and National Oceanic and Atmospheric Administration.

Some of those slabs landed on the reef. The agencies said the state should plan to restore the damaged coral.

The agencies' "Keawakapu Preliminary Injury Assessment," issued March 16, also did not delve into how the accident occurred or who is responsible.

More investigation is required to determine a variety of issues, such as the damage done to the underwater species and measuring the actual size of the live reef, according to the report.

The slabs hit live coral while the state's contractor, American Marine Corp., placed the concrete reef modules in a 5-acre area within the 52-acre Keawakapu artificial reef. The report did not say if state employees were onboard overseeing the operation.

The Keawakapu reef is made up of 150 cars, a sunken ship, 35 other concrete slabs and thousands of tires. The slabs that didn't hit the live coral landed safely on the sand or patches of algae, according to the report.