Hospital staff could struggle to cope in the wake of a plane crash or terrorist attack if vital cleaning facilities are moved nearly 10 miles away according to opponents of the plans.
Health campaigners insist bosses at West Middlesex Hospital have failed to account for the risk of a human disaster as they push ahead with plans to shut their on-site sterilisation unit.
They fear there would be too few instruments on site to deal with casualties from a major catastrophe if the department is transferred to a regional centre in Ruislip next year.
Jean Doherty, former head of hospital watchdog West Mid Patient and Public Involvement Forum, said: "If there was a tragedy such as a big plane crash at Heathrow, what would they do?"
She argues that if a large volume of instruments were needed quickly, they may well be unavailable, trapped in grid-locked traffic surrounding the incident.
John Hunt, another ex-forum member, said: "If you don't have an amount of supplies accountable for any situation there may be trouble.
"I recall there were problems when Birmingham Hospital outsourced its sterile services. They would get a batch of instruments for a day's operations then find that there were problems with what had been delivered. There was no contingency, so whenever this happened operations would have to be abandoned and delayed.
"I know staff at the hospital are not happy with these plans, not just staff from the sterilisation department but consultants and nurses too, people from all sorts of different departments."
A hospital spokesman said: "West Middlesex is a designated hospital for major incidents and has robust plans in place to respond accordingly, as was the case with the London bombings a few years ago.
"Depending on the type of major incidents, there can be a requirement for additional supplies and we have ensured that there are a range of provisions within the new contract for urgent delivery of equipment.
"Furthermore, being part of the North West London Decontamination Partner-ship, we will be able to pool resources with other local trusts to ensure enough equipment is readily available."