The contractor who built the 17,000-square-foot expansion at the Hollings Marine Laboratory on James Island was "clearly negligent" in designing a building that endangered workers' safety, federal officials said.

About 40 employees were forced out of their offices in the new $8.5 million wing this summer because the poorly designed building was susceptible to collapse, according to an e-mail response from the National Oceanic and Atmospheric Administration, the federal agency that runs the lab.

Hollings employees first noticed a problem about six months earlier, when they saw cracks inside the building and in the foundation, according to the e-mail from NOAA spokesman Ben Sherman.

Although the contractor, SEI Group of Huntsville, Ala., signed off on construction documents showing that it complied with code requirements, two independent consultants reported "design omissions and serious concerns" with the building's load-bearing capabilities when they surveyed the damage in February, Sherman wrote.

"The contractor was clearly negligent in providing quality control oversight," according to Sherman's e-mail. "The structural engineer on the design team failed to meet the responsibility to design a safe, structurally sound building that meets all applicable structural codes."

SEI Group must pay to fix the expansion, which housed labs with

running water, sinks and drains where biological experiments could be conducted, NOAA officials have said. Vice President Brian Osterndorf, a spokesman for the firm, declined comment Friday.

SEI Group, which NOAA selected to design and build the project from among a group of four possible contractors, "has taken full responsibility for correcting the problem and has acknowledged accountability for their errors and omission," Sherman wrote in his e-mail.

The contractor is expected to propose a solution by the beginning of next week.

The fixes are expected to take at least a year to complete, Sherman said. It is not clear how much the repairs will cost, he said.

Meanwhile, the S.C. State Board of Registration for Professional Engineers and Surveyors, a branch of the state Department of Labor, Licensing and Regulation, has opened its own investigation into the design failure, department spokesman Jim Knight said.

Reach Renee Dudley at 937-5550 or rdudley@postandcourier.com.