A blame-game has erupted at the Indian Museum in Kolkata, India after construction workers performing “routine maintenance” badly damaged a priceless artifact, the Times of India reports.

On Monday, workmen from the National Building Construction Corporation (NBCC) broke a glass display case holding a votive stupa from the first century AD, and the falling glass shards damaged the fragile ancient artifact.

Made of schist—a rock which reacts to sand—the votive stupa from the Gandhara region is a very important historical artifact. In the first century Indo-Greek, Indo-Persian and Mauryan settlers called the area home, and the artifact reflects the diversity of the region in which it was created.

Ashok Tripathi, a spokesperson for the Indian Museum, explained “As per the advice by Archeological Survey of India (ASI), the NBCC workers were putting silica gel inside the case to control the moisture and prevent flaking. That is when the glass top broke and fell into the case.”

“According to the contract, these artifacts are under NBCC’s supervision. Indian Museum officials have nothing to do with it,” Tripathi insisted, adding that the stupa will be sent to the preservation section for restoration.

However, an unnamed senior museum official reportedly claimed that the NBCC contract expired on March 31. “It is ridiculous to say that the artifacts are under supervision of NBCC. It is not only an offense, but a serious breach of security. [The] entire security section of Indian Museum was in the dark about this maintenance work.”

Regional Director of the ASI, Dr. P.K. Mishra, lamented “If the damage is irreparable, the loss will not be confined to the museum. It is a loss for the entire world.”

Meanwhile, Sachindranath Bhattacharyya, a Trustee member of the Indian Museum Board, demanded an explanation, saying “This is the sixth incident of vandalism in a row. There has to be an end to such careless handling of artifacts.”

Although museums are generally safe environments for antiquities, accidents sometimes happen and it’s not uncommon for artifacts to endure damages (see King Tut Damaged in Botched Repair Attempt and King Tut’s Chair Damaged During Transport to New Giza Museum)