This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

NEW YORK — Are hand dryers in public restrooms blowing bacteria back on your freshly washed hands as you’re drying them?

PIX11 collected samples from a variety of restrooms in the city and, working with a nationally recognized lab, put them to the test.

Take a closer look at that hand dryer in the bathroom and you’ll likely see filth, dirt and dust. What you won’t see is potentially dangerous bacteria.

“If you wash your hands then dry your hands, you’ll want to wash your hands again,” said Vincent Iuzzolino, microbiology laboratory director of EMSL Analytical Services.

Proponents of hand dryers say they’re energy efficient, cost effective and environmentally friendly as an alternative to paper towel waste. But the concern lies in the fact that dryers don’t just blow air out, they siphon in air.

With bathrooms being generally dirty places, that air contains pathogens, microbes left behind from people’s skin or people flushing lidless toilets. The dryers then suck the germs in and spew them out again onto freshly washed hands.

There have been several recent studies that found dryers are trapping bacteria from restrooms and blowing them onto hands.

PIX11 did its own test, collecting grime from 10 dryers in bathrooms at major locations around the city. The locations were chosen at random and included popular locations like transit hubs, parks, restaurants and stores.

“If there are currents, that bacteria can become airborne. If it lands in a place where there are nutrients and moisture, those bacterial cells can start to divide and then multiply,” Iuzzolino said.

“Even if you start out with just a few bacterial cells, over time, in the appropriate conditions, you’ll have actually lots of growth. When that bacteria gets in the air, of course, it can land on the dryers themselves and then when the dryers are turned on, it’s a very powerful blower and then it would blow air into the environment.”

PIX11 collected the samples, following the testing protocol of EMSL, based in Cinnamonson, N.J.

Once the lab received those swab samples, they diluted them in sterile water then they plated them on a type of media so the bacteria can grow on and the microbiologists can study it.

“You can see there’s quite a variety of organisms growing on there,” Iuzzolino said, showing us the plate. “We’re then able to run through our identification system and, basically, it’s a mass speck that identifies the bacteria through profile and compares it to the library so the identification process is very, very precise. Most people in the healthcare industry, microbiologists, would be concerned about those results. We had some that were in the millions.”

As in, millions of bacteria.

“We found klebsiella. We found enterobacter. We found enterococcus faecalis,” Iuzzolino said.

“We identified quite a few different organisms, of course, particularly in the places where you had high levels of bacteria. These are generally found widely distributed in the environment but also it’s part of our intestinal tract.”

The dirtiest hand dryers tested were: a World Dryer machine inside a bathroom in Central Park; the Xlerator in a busy Union Square grocery store; the Dyson Airblade model in a popular Times Square restaurant and one in a women’s restroom at the Oculus. They all tested for a large number of bacterial colonies.

Central Park released the following statement:

“The Central Park Conservancy cleans the bathrooms in Central Park three to four times daily.”

The manufacturer of Xlerator said:

“Excel Dryer is committed to providing hygienic, sustainable and cost-effective hand drying solutions that people can depend on. As with any piece of equipment or fixture in a restroom, like sinks or toilets, hand dryers must be properly cleaned and maintained to achieve their intended performance. Our product manuals, shipped with each product and available online, contain instructions for proper cleaning and maintenance. We have reached out to the location to review the proper care instructions and inform them about our available hygiene accessories including a HEPA filtration system and antimicrobial wall guards. It is of the upmost importance that all our customers are pleased with our products and that they are performing properly.  Without knowing the science or methodology used in the testing, we cannot comment further, but would be very interested to learn how the study was performed. In addition, here is a link to the product manual which details cleaning instructions, for your convenience.”

The Dyson Airblade is built to contain a HEPA filter and it’s the responsibility of businesses to change the filters according to guidelines set by Dyson.

Dyson issued the following statement:

“Dyson Airblade TM hand dryers are proven hygienic by university research, and are the solution to environmentally impactful paper towels. When Dyson Airblade TM hand dryers are maintained in accordance with our cleaning recommendations, microbes on the machine surface will not be an issue. Swabbing any washroom surface is likely to reveal microbes, illustrating the importance of regular cleaning. We’re supporting the locations mentioned to make things right.”

The most common bacteria discovered in the samples, like klebsiella and enterobacter, can be found in fecal matter. They can lead to a range of illnesses: respiratory, skin, eye, abdominal infections, even septicemia, a blood infection.

Scientists stress that people with compromised immune systems, children or the elderly are more susceptible to these so-called “opportunistic organisms.”

“As an example, someone who has an open cut on their skin and bacteria gets in, you could get a skin infection,” Iuzzolino said. “Some of what we tested was really very clean compared to some that we tested that were pretty inundated with microorganisms.”

The microbiologist PIX11 spoke with said the silver lining is that more dangerous bacteria like E. coli or Salmonella were not found. Still, the levels of bacteria were very high.