Metro Grade: How dirty is Metro, and does it matter?

Each week, we evaluate Metrorail service and, with the help of some of our friends, present a report card. Watch out, WMATA, or we'll make you return it with a parent's signature.


What do makeup samples, sushi and the Metro have in common? They are all host to a variety of bacteria.


Testing Metro: Where the bacteria live27 Photos

Long story short

Should Metro riders be worried about germs? TBD has the answer.


We followed last week’s underground incubator to see if the bacteria we swabbed from the Metro was any more or less disconcerting than what we might find at the mall or in our offices.

After a week of harvesting bacteria in the deepest, darkest depths of Mandy Jenkins’ cubicle, the results are in and we have our winners. Escalator handrails, trashcans, exit fare buttons and maps seemed to develop the most colorful and furry colonies.

Dr. Nancy Zeller, microbiology professor and director of biology teaching laboratories at American University, gave our experiment a pat on the back, recognizing that none of us have science degrees but can still grow some mean bacteria colonies. She offered both interest and insight into our study.

“I think about this when I race down the escalator and I’m grabbing the handrails,” she said. This concern led Dr. Zeller to her own predictions for the Metro's dirtiest surfaces. “I’m thinking the escalator handrails and the seats have the most bacteria."

Dr. Zeller examined our results and explained why some of the samples looked exceptionally large and disgusting.

“Wherever there’s a public place, it is loaded with germs,” she said. “When you touched your cotton swab to a surface and then smeared it on the agar in the petri dish, the agar provides food and nourishment. Then the cells start dividing. In a matter of days, you can have a large bacteria colony.”

We certainly did.

Dr. Zeller said it would be impossible to tell if there were potential pathogens in the bacteria we observed, but she suggested we look at the color and amount to see what types of bacteria we were dealing with and which locations underground were prone to more bacteria growth. The white and yellow spots found most frequently in our samples are common almost everywhere, as they are often found in the air. The pink and orange spots are only slightly less common and simply suggest that multiple types of bacteria exist on those surfaces. Finally, the black fuzzy growths resemble bread mold and are most likely very similar to the bacteria we encounter in bad food.

This black “mold” was found on a map in an Orange Line train rolling through Farragut West, on a bench in Chinatown, a handrail on a Green Line car and a door at Union Station. This might have been the most concerning growth we found in our petri dishes, but it was also found in one of our control samples from around the TBD office… the sample from my laptop. Gross.

The reality is that the Metro grows some pretty scary-looking bacteria, but so does your laptop. Yes, the Metro could certainly be cleaner, but so could we. That being said, Dr. Zeller is confident that the TBD Science Club has been much better recently about sanitizing our hands and keeping germs to ourselves.

“The public is doing a better job now than before,” she said. “People cough into their elbows more often than their hands. There’s a greater level of consciousness because of the publicity that the H1N1 virus and the flu received.”

Dr. Zeller also confirmed that not all bacteria are bad for us.

“There are very few species of bacteria that cause disease,” she said. “A lot of bacteria are actually good for us. Some help us digest our food.”

I wouldn’t count on any Metro bacteria to cure indigestion, but I won't be avoiding handrails and open seats when I need them. Only the trashcans, maps and exit fares. Those will stay off-limits.

Germs aside, let’s see how Metro fared this week.

Please keep in mind that these grades were tallied before the escalator collapse at Foggy Bottom this morning, which is really going to screw up WMATA's grades next week.


WMATA Report Card - February 18, 2011
Grade Subject
D Safety
Between Metro fights and police activity at Glenmont, it seems like the Metro is a good place to go if you're looking for trouble.
D Reliability
Every line (or pair of lines) suffered from several train malfunctions this week, causing more than 20 delays. The Red and Green Lines are tied for least dependable.
A Health and Wellness
No sick passengers reported. Maybe the Metro germs aren't so bad. Thank you, cleaning crew. Keep up the good work!