SHANGHAI -- A gas explosion at a Pegatron-owned metal casing factory here injured 61 workers, putting 23 in the hospital, the company reported.

The facility was still under construction and was running trial production when the accident occurred on Saturday, according to several reports, including Reuters.

The factory is owned by Ri-Teng Computer Accessory, a subsidiary of Pegatron, one of the largest electronics original design manufacturing companies and a rival to Foxconn.

The factory will supply to Apple, which says it is "working closely with Pegatron to understand the cause" of the accident.

Pegatron becomes the latest Apple supplier to experience a startling workplace disaster. Earlier this year, Foxconn had fires at its Shangong and Chengdu sites; at the latter, three workers were killed. And a Catcher metal chassis facility in Suzhou was temporarily closed in October due to odorous gas emissions.

Apple says it is committed to diving the highest standards of social responsibility throughout its supply base. However, internal audits of its corporate code of supplier responsibility (CSR) practices over the past two years have revealed scores of violations.