It is alleged that Gillian Beckingham, a Barrow Borough Council architect, cancelled a maintenance contract which provided the safety measures of an air-conditioning unit at the Forum 28 art centre in Barrow-in-Furness.
Preston Crown Court heard that in July 2002 the system sprayed deadly bacteria into the air, leading to an outbreak of Legionnaires' disease, in which six women and one man died, while 172 others fell ill.
During the trial, which commenced on June 8, the court also heard that the deaths were both 'avoidable and unnecessary'.
Alistair Webster QC, prosecuting, told the jury: 'It was an outbreak, which could have been avoided by the exercise of no more than a moderate amount of care and common sense.
'These were deaths with all the consequence, trauma and sadness for the families and victims infected, which we say were avoidable and unnecessary,' he told the court.
The prosecution alleges that all seven deaths were due to Legionnaires' disease, which is an acute form of pneumonia.
However, the defence disputes whether two of the deaths were the direct result of the disease.
Beckingham, who was the council's head of design services at the time, denies the manslaughter of the seven victims and the health and safety breaches.
In her defence, she told the court she had never received any health and safety training from the council.
At an earlier trial, Barrow Borough Council, which owns Forum 28, was cleared of corporate manslaughter, but pleaded guilty to breaching the Health and Safety at Work Act.
The jury in the current trial is expected to retire to consider its verdict today.