The Privacy Commission is investigating how a large quantity of confidential documents - including details of hospital patients, application forms for a TV service and receipts from a clothing chain plus student exam papers - came to be dumped near a recycling firm's offices in Fan Ling.
More than 80 boxes of documents were found near the offices of Fook Woo Group on Kui Sik Street on Sunday.
The boxes held records of patients at Our Lady of Maryknoll Hospital, application forms for i-Cable connections, customer receipts from G2000 and papers for this year's Hong Kong Diploma of Secondary Education set by the Hong Kong Examinations and Assessment Authority.
Some G2000 receipts gave credit card and mobile phone numbers of customers.
An official at the Office of the Privacy Commissioner for Personal Data said investigators were first checking with the data users "to have a better understanding of the incident." There would not be any comment until after that was done.
The Personal Data (Privacy) Ordinance stipulates that "all practicable steps" need to be taken to ensure that personal information on people held by another party is protected against unauthorized or accidental access, processing and erasure.
A spokesman for G2000 said the company hired Fook Woo Group to shred the confidential documents.
"We are gravely concerned," he added. "We had given clear guidelines to the recycling company on how confidential documents should be handled and shredded. We have already demanded the company launch an investigation into the incident."
A spokesman for Our Lady of Maryknoll Hospital said it too had asked its contractor handling the documents to investigate and provide an explanation.
There was also the question of whether a disposal contract had been breached.
Generally, he added, contractors in this line of work must submit proof to the hospital within a month to certify that documents taken away have been shredded.
Both i-Cable and the Hong Kong Examinations and Assessment Authority also said they had ordered their document-disposal contractors to check the facts.