Student or Learner
"Government records show high levels of legionella were found in 15 of the 464 buildings - a fraction of the hundreds of thousands in our city - inspected in the past eight months. The outbreak of severe acute respiratory syndrome nine years ago taught us the link between buildings and health and the importance of design, construction, maintenance and inspections. That message has been reiterated by the findings at Tamar. With legionnaires' disease, that puts the onus of prevention on owners, engineers and contractors" (SCMP, HK)
What does "that" refer to in the last sentence.? Is "that" just refer to something conveyed previously without any precise meaning, only used to fill in the "subject position" in the sentence?
Thanks for any reply!!