Mr Macniven also said that coding of the causes of death was being updated to take account of changes to the World Health Organisation's international classification of diseases and related health problems.
Right now hospital coders use a standard called the International Statistical Classification of Diseases and Related Health Problems to classify patients and get reimbursed properly for their care.
They could have to pay back taxes in addition to potential penalties associated with the health-care law, should the revised classification push their employee headcount over the threshold.
The anti-smoking charity Action on Smoking and Health has written to the British Board of Film Classification drawing attention to the findings and requesting that smoking be included in the decision about certification.
Most diagnoses in the UK are based on the International Classification of Diseases (ICD), published by the World Health Organization, which is up for revision in 2015.
The ONR, which is an agency of the Health and Safety Executive, said the use of unencrypted devices for transporting documents with a security classification was not allowed.