Chinese medical authorities have confirmed that nine employees of China’s second largest oil company Sinopec have tested positive for coronavirus.

The nine are all tested positive with the virus upon arrival at Qingdao airport in China on July 17, although eight have showed no symptoms,

They are employed by Sinopec for work at an unidentified project in Kuwait and flew back to China on a chartered Air China plane.

They are being quarantined at a designated hospital for treatment.

These are the first confirmed cases involving employees of China’s national oil companies.

Sources said that the nine Sinopec employees may have been working on the Al-Zour refinery, which is located about 90 kilometres south of Kuwait City.

In April, Sinopec built a make-shift hospital by turning its supply base once used for building the Al-Zour refinery in Kuwait to cater specifically for the treatment of coronavirus patients in Kuwait.

It is not clear if other workers still working on the refinery in Kuwait have tested Covid-19 positive.

Sinopec is the engineering, procurement and construction contractor of the 615,000-barrels-per-day refinery, which was commissioned late last year.