A Jehovah's Witness died after a doctor ruptured her spleen and liver during a routine procedure.
Despite suffering massive internal bleeding, Jean Gilman refused to have a blood transfusion and died four days later.
Medical staff at Whiston Hospital were later investigated over a potential manslaughter charge but the Crown Prosecution Service ruled there was insufficient evidence to proceed.
Hospital bosses last week apologised to Mrs Gilman's family and admitted mistakes in her initial treatment.
But her family are still angry and insist they have expert testimony stating a blood transfusion would NOT have saved Mrs Gilman.
Her widow Peter, 62, of Porlock Avenue, Sutton Leach, said: "By the time she was operated on it wouldn't have helped to have blood transfusion.
"Anyway, that it not really the issue. The issue is that they knew she was a Jehovah's Witness and would not have taken blood products, so carrying out that procedure in the way they did was even more reckless."
A mum of three, Mrs Gilman had three grandchildren and had been a Jehovah's Witness for almost 40 years.
She was taken to Whiston Hospital in March 2009 after going to her GP complaining of shortness of breath.
X-rays showed she had had fluid on her left lung requiring a pleural aspiration to remove the fluid.
However, rather the follow British Thoracic Society Guidelines and use to an ultrasound machine to locate the fluid, the doctor attempted to guess where to insert the needle.
Later that day her health began to deteriorate and that night she rushed into the hospital's operating theatre suffering massive internal bleeding.
Four days later she was dead.
Mr Gilman, a retired chemical plant manager, said: "I was with her on the Friday afternoon and we were talking, saying that she might be allowed home that day, when a pair of doctors came in and said they were going to drain the fluid from Jean's lung.
"He then inserted the needle about four times, but each time he just drew blood, not fluid. Then they just left. There was no explanation, nothing."
The family say despite signs her health was rapidly deteriorating medical intervention came too late - although the hospital insist her treatment was 'timely and appropriate'.
The full picture and the fact the plural aspiration procedure had ruptured Mrs Gilman's internal organs only emerged when St Helens coroner Christopher Sumner refused to sign off her death certificate and ordered a post-mortem by conducted.
Once the police probe ended, the Gilman family launched a civil case, which culminated last week when the hospital trust's chief executive Ann Marr wrote to Mr Gilman.
He said: "In the letter, she apologised and said there would now be a 'serious untoward incident' review. Why has it taken so long for this?
"As far as we know the doctor in question is still working, although not at Whiston. We are now just waiting for the inquest to try and get more answers."
A hospital spokeswoman said: "Mrs Gilman underwent a procedure carried out by a senior doctor who had performed this procedure many times. On this occasion the doctor did not follow guidelines and made a mistake.
"Thereafter, she received timely and appropriate care but as a Jehovah's Witness she chose not to receive blood products and her life could not be saved.
"A subsequent police investigation concluded that no charges should be brought against any party. The Trust would like to offer again its sincere condolences to the family of the late Mrs Jean Gilman".