Hospitals are putting patients' lives at risk by not getting rid of clinical waste properly, according to spending watchdogs.
Hospital waste is putting lives at risk, watchdogs warn
Inspectors found that in a third of NHS hospitals, clinical waste was not being stored safely out of patients'reach.
Audit Scotland also said hospitals were squandering more than £1m a year by mismanaging waste disposal.
Health Minister Andy Kerr is to tell health boards to improve performance as a result of the findings.
Research was carried out in 53 hospitals, from Dumfries and Galloway to Ninewells in Dundee.
More than a third were storing rubbish in places such as public areas or in unlocked bins.
Auditors defined clinical waste as including infectious and potentially infectious material such as blood contaminated items, human tissue and used syringes.
Spokeswoman Caroline Gardner called on NHS boards to tighten up procedures to safeguard both the public and staff.
Analysts also found that hospitals were failing to separate domestic and clinical waste effectively, at an unnecessary cost of £1.3m.
Mr Kerr said it was "completely unacceptable" for clinical waste to be in rooms where the public had access.
The minister said a change of contractor since the study was completed had "largely" addressed the problem.
"However, the fact that some NHS boards have failed to tackle relatively straightforward waste management issues is not good enough," he added.
"These must be accorded a high priority by NHS managers.
"I will issue clear instructions to boards to improve their performance and I will be keeping a very close eye on progress."
Scottish National Party health spokeswoman Shona Robison said: "This is simply not good enough.
"Given public concern over infection levels and the rise of MRSA and hepatitis B in the UK, this report clearly indicates that the executive is failing to tackle health and safety in Scottish hospitals."