Amid a cluster of white hazmat suits on Wednesday in Dallas, as the second US nurse to contract Ebola was loaded onto a plane bound for Atlanta, was a lone official with no protection whatsoever.

The official - as yet unidentified - wore just a button-down shirt and trousers as he held a clipboard and directed the operation at Love Field airport.

He then flew with the nurse, who has been identified as Amber Vinson, and the hazmat-suited team to Atlanta, where local TV crews spotted him with Vinson's stretcher as she was disembarked at the airport in Georgia to be transferred to Emory University Hospital.

The incident has triggered amazement and a social media storm, due to the ease with which Ebola - a virus which has killed more than 4,000 people in West Africa and which has now spread beyond its borders to Europe and the United States - can be contracted.

While Ebola is not an airborne disease, his proximity to Vinson's medical team and his visible interaction with the patient has sparked fears.

Ebola is spread when people have direct contact through broken skin, or the mouth and nose, with the blood, vomit, faeces or bodily fluids of someone with Ebola. Infection can also occur via direct contact with contaminated bedding, clothing and surfaces.

He was even seen grabbing a container and hazmat trash bag from one of the workers in full-protective gear before boarding the flight.

According to ABC News, the man is a supervisor for Phoenix Air, the company that flew Miss Vinson from Dallas to Atlanta.

Members of the public watching were struck with disbelief at the man's decision to throw caution to the wind.

"He needs to be put on watch the second the plane lands so he does not infect anyone in Atlanta. This needs to be contained and I for one will be ticked if I hear a report next week that he is the next victim!" Dean Pitts wrote on NBC Dallas' website.

Phoenix Air operates the special air ambulances that have flown all five American Ebola patients from West Africa to the US reckoned there was "no problem". It said the unprotected man actually made the process safer.

"Our medical professionals in the biohazard suits have limited vision and mobility and it is the protocol supervisor's job to watch each person carefully and give them verbal directions to ensure no close contact protocols are violated," a Phoenix Air spokesman told ABC.

It ensures "an even higher level of safety for all involved", the carrier said.

A spokesman for the US Centres for Disease Control (CDC) told KTVT that it did not think anything was wrong with the interaction since the official "kept a safe distance".

Vinson's flight landed in Atlanta at around 7.45pm Eastern Time (7.45am Singapore time).

Social media was dumbfounded by the man who has quickly become known as "Clipboard Man" online.

Said one incredulous witness, "My infectious disease training may be a bit limited but fairly sure that clipboard isn't Ebola proof."

Said "waslefthomeagain" on the ABC News site: "So let me get this straight: one protocol procedure for close contact is wearing a hazmat suit; the second procedure is a guy not in hazmat ensuring the others are wearing hazmat... properly. I get it. Scientists, you crazy..."

Clipboard Man is not the first instance of the CDC being questioned over its handling of Ebola in the US - which began when Liberian patient Thomas Eric Duncan was turned away from Texas Health Presbyterian Hospital last month after reporting a high fever.

Despite telling health-care workers that he had recently returned from Liberia, in West Africa, he was not tested for Ebola, and was instead sent home with antibiotics.

He returned home to his family's apartment and continued to get worse over the next several days. It was only when he was taken to the hospital a second time, that time by ambulance, that medics discovered he had Ebola.

In the initial days of Duncan's treatment, nurses at the Dallas hospital revealed that they were given "no protocols" on how to dress when caring for the Ebola patient.

Later, nurse Nina Pham, 26, contracted the bug, followed by co-worker Vinson.

The CDC is currently monitoring more than 75 health-care workers at the hospital who came into contact with Duncan during his stay. He passed way from the disease last week.