Working as the Chief Hospital Engineer. 3 x deaths occurred as a result of Legionnaires Disease (LD). CDSC & Public Health Team become involved and David is part of team who trace this back to the Cooling Towers.

As a direct result of a suggestion from David, and thereafter born as a concept, David works in collaboration with Chris Bartlett (Dep. Director of PHE), alongside Horne as the manufacturer.

First UK Outbreak of LD to occur within and industrial setting. David finds the source, in this case associated to Cooling Towers and engineers it out!

David begins work across the UK for the Public Health Laboratory Service. (PHLS)

David is based aboard SS Canberra as the Public Health Officer (PHO) with the responsibility of protecting the troops from potential environmental disease and ensuring the safety of food and water on board. This is the first time the term “Authorising Engineer (AE) is used” and David is the first to receive this title and recognition.

David begun lecturing for this organisation, providing invaluable practical and technical training to both individuals and organisations within the water hygiene and management segments.

While continuing to work for Kingston Hospital, David was seconded to Government, and asked to be part of the team at Public Health England (PHE). Working as the Senior Engineer, David was tasked to carry out water related investigations across the UK and conduct “Hazard Assessments” (now known as modern Water Risk Assessments) across all industry segments.

David investigated following a number of LD related fatalities associated with the Cooling
Towers at the BBC in Oxford Circus. Following this incident, David was asked to write a further guidance paper about LD for the HSE. This then became the EH48 Guidance which contributed to and formed the basis of today's HSE ACOP L8.

David consulted following an environmental concern surrounding an outbreak of food poisoning.

Request HSE Documentation from post BBC Outbreak to become Law. This becomes ACOP L8, which still has a lot of references to D Harper's orginal work.

Assessing water system effectiveness, safety, and compliance on board a submarine vessel for a specific project.

David begins work with WTI, the training division of Water Authorities across the UK. David becomes instrumental in the early days of this set-up and plays a pivotal role in helping the organisation to provide City and Guilds Accredited qualifications.

A Toxicity case was investigated by David, leading to the discovery of drinking water contamination arising from a mobile phone which had been inadvertently dropped into the water tanks during routine maintenance work.

David Harper appointed to initially carry out Risk Assessments for all UK Hotel premises within the IHG portfolio. This subsequently expanded to International assets and premises and led to the formation of the IHG Water Policy, which was instigated and approved by David.

7 deaths and 180 people people fall seriously ill following the largest LD outbreak recorded until now. This was the result of poorly managed water systems within a town centre council owned Arts and Leisure Facility. The water-cooled air conditioning system was found to be the source and David was integral to the investigation and contributed to the legal case that followed.

Drinking water originating from a Bore-Hole proved to be contaminated from the landfill above it and from the Incinerator source. The Island's drinking water supply was compromised, resulting in toxic poisoning. It fell to David to put in place counter measures and longer terms sustainable actions to avoid this from reoccurring.

Appointed as Authorising Engineer for Water to ensure Water Policy is compliant and that all appropriate stakeholders are involved and accountable.

Grandfather (63) dies after contracting LD. As leading investigator, David traces the source to stagnant water which was used to clean his terrace.