A top U.S. biosecurity lab is taking responsibility for signing “poorly drafted” agreements with three high-level biosecurity labs in China that they concede may have broken the law.

The three contracts, including one with the Wuhan Institute of Virology (WIV), gave the Chinese labs the power to destroy “secret files” from any stage of their collaboration.

“The party is entitled to ask the other to destroy and/or return the secret files, materials, and equipment without any backups,” reads the 2017 memorandum of understanding (MOU) that the University of Texas Medical Branch (UTMB) signed with the Wuhan lab, which was revealed in April.

The broad confidentiality obligation, renewable every five years, applies to “all cooperation and exchange documents, data, details and materials,” according to the document.

Located in the city where COVID-19 began its spread, the WIV, which for years conducted coronavirus research with U.S. funding, has attracted global attention as a possible source of the virus.