How Do They Dye the Chicago River Green for St. Patrick's Day?

iStock.com/stevegeer
iStock.com/stevegeer

It wouldn’t be a St. Patrick’s Day celebration in the Windy City without 400,000 spectators crowding the banks of the Chicago River to “ooh” and “aah” at its (temporarily) emerald green tinge. But how do officials turn the water green?

First, a bit of history: The dyeing tradition became an annual thing nearly 60 years ago, in 1962, but its real origins go back even further. In the early days of his administration as Mayor of Chicago, Richard J. Daley was a man on a mission to develop the city’s riverfront area. There was just one problem: The river itself was a sewage-filled eyesore. In order to get to the bottom of the city’s pollution problem and pinpoint the exact places where waste was being discarded into the waterway (and by whom), Daley authorized the pouring of a special green dye into the river that would allow them to see exactly where dumping was occurring.

Fast-forward to late 1961 when Stephen Bailey—part of the Chicago Journeymen Plumbers Local, the city’s St. Patrick’s Day Parade chairman, and a childhood friend of Daley’s—witnessed a colleague’s green-soaked coveralls following a day of pouring Daley’s dye into the Chicago River. That gave Bailey an idea: If they could streak the Chicago River green, why not turn it all green?

Three months later, revelers got their first look at an Ecto Cooler-colored river when the city poured 100 pounds of the chemical into the water. They got a really good look, too, as the river remained green for an entire week.

Over the next several years, the same practice was repeated, and again it was carried out by the Plumbers Local. The only difference was that the amount of dye used was cut in half over the next two years until they finally arrived at the magic number: 25 pounds of dye = one day of green water.

Unfortunately, the dye that was intended to help spot pollution was an oil-based fluorescein that many environmentalists warned was actually damaging the river even more. After fierce lobbying, eco-minded heads prevailed, and in 1966 the parade organizers began using a powdered, vegetable-based dye.

While the exact formula for the orange powder (yes, it's orange until it's mixed with water) is kept top-secret—in 2003 one of the parade organizers told a reporter that revealing the formula would be akin to “telling where the leprechaun hides its gold”—there are plenty of details that the committee lets even non-leprechauns in on.

The dyeing process will begin at 9 a.m. on the morning of the parade—which this year is Saturday, March 16 (it's always held on a Saturday) when six members of the local Plumbers Union hop aboard two boats, four of them on the larger vessel, the remaining two on a smaller boat.

The larger boat heads out onto the water first, with three members of the crew using flour sifters to spread the dye into the river. The smaller boat follows closely behind in order to help disperse the substance. (The best place to catch a glimpse is from the east side of Michigan Avenue, or on Upper and Lower Wacker Drive between Michigan Avenue and Columbus Drive.)

Approximately 45 minutes later, voila, the Chicago River is green—but don’t expect it to stay that way. These days, the color only sticks around for about five hours. Which is roughly the same amount of time it takes to get a perfectly poured pint of Guinness if you venture out to an Irish pub on St. Patrick’s Day.

A version of this article first ran in 2017.

Have you got a Big Question you'd like us to answer? If so, send it to bigquestions@mentalfloss.com.

How Does Alberta, Canada, Stay Rat-Free?

Francisco Martins/iStock via Getty Images
Francisco Martins/iStock via Getty Images

David Moe:

Alberta is the only province in Canada that does not have any rats and is, in fact, the largest inhabited area on the planet that is rat-free. Rats had to come from Eastern Canada, and it’s a long walk, so it was not until the 1950s that they finally reached Alberta. When they did, the Alberta government was ready for them: They instituted a very aggressive rat control program that killed every single rat that crossed the Alberta/Saskatchewan border.

The Agricultural Pests Act of Alberta, 1942 authorized the Minister of Agriculture to designate as a pest any animal that was likely to destroy crops or livestock; every person and municipality had to destroy the designated pests. Where their pest control was not adequate, the provincial government could carry it out and charge the costs to the landowner or municipality.

Rats were designated as pests in 1950. An amendment to the act in 1950 further required that every municipality appoint a pest control inspector. In 1951, conferences on rat control were held in eastern Alberta, and 2000 posters and 1500 pamphlets titled "Rat Control in Alberta" were distributed to grain elevators, railway stations, schools, post offices, and private citizens.

Between June 1952 and July 1953, [more than 140,000 pounds] of arsenic trioxide powder were used to treat 8000 buildings on 2700 farms in an area 12 to 31 miles wide and 186 miles long on the eastern border. Some residents were not informed that arsenic was being used and some, allegedly, were told that the tracking powder was only harmful to rodents. Consequently, some poisoning of livestock, poultry, and pets occurred. Fortunately, Warfarin—the first anticoagulant rodent poison—became available in 1953; Warfarin is much safer than arsenic, and in fact is prescribed to some heart patients as a blood thinner.

The number of rat infestations in the border area increased rapidly from one in 1950 to 573 in 1955. However, after 1959, the numbers of infestations dropped dramatically.

The provincial share of rat control expenses increased to 100 percent in 1975. All premises within the control zone from Montana to Cold Lake are now inspected at least annually. Rat infestations are eliminated by bait, gas, or traps. Buildings are occasionally moved or torn down, and in some cases, rats are dug out with a backhoe or bulldozer. In the early days they also used shotguns, incendiaries, and high explosives to control rats. It was something of a war zone.

Hundreds of suspected infestations are reported each year, but most sightings turn out to be muskrats, pocket gophers, ground squirrels, bushy-tailed wood rats, or mice. However, all suspected infestations are investigated.

A few white rats have been brought in by pet stores, biology teachers, and well-meaning individuals who did not know it was unlawful to have rats in Alberta, even white lab rats or pet rats. White rats can only be kept by zoos, universities, colleges, and recognized research institutions in Alberta. Private citizens may not keep white rats, hooded rats, or any of the strains of domesticated Norway rats. Possession of a pet rat can lead to a fine of up to $5000.

In 2004 someone released 38 rats in Calgary. By the time the rat control officers arrived, most of them were dead. The local residents had formed a posse and killed them with brooms, 2x4s, and shovels. If the authorities had caught the culprit, he could have faced a $190,000 fine (38 x $5000)—assuming his neighbors didn’t get to him with brooms, 2x4s, and shovels first. Albertans don’t want rats.

This post originally appeared on Quora. Click here to view.

Why Do Students Get Summers Off?

Iam Anupong/iStock via Getty Images
Iam Anupong/iStock via Getty Images

It’s commonly believed that school kids started taking summers off in the 19th century so that they’d have time to work on the farm. Nice as that story is, it isn’t true. Summer vacation has little to do with tilling fields and more to do with sweaty, rich city kids playing hooky—and their sweaty, rich parents.

Before the Civil War, farm kids never had summers off. They went to school during the hottest and coldest months and stayed home during the spring and fall, when crops needed to be planted and harvested. Meanwhile, city kids hit the books all year long—summers included. In 1842, Detroit’s academic year lasted 260 days.

But as cities got denser, they got hotter. Endless lanes of brick and concrete transformed urban blocks into kilns, thanks to what was known as the “urban heat island effect.” That’s when America’s swelling middle and upper class families started hightailing it to the cooler countryside. And that caused a problem. School attendance wasn’t mandatory back then, and classrooms were being left half-empty each summer. Something had to give.

Legislators, in one of those if-you-can’t-beat-‘em-join-‘em moments, started arguing that kids should get summers off anyway. It helped that, culturally, leisure time was becoming more important. With the dawn of labor unions and the eight-hour workday, working adults were getting more time to themselves than ever before. Advocates for vacation time also argued (incorrectly) that the brain was a muscle, and like any muscle, it could suffer injuries if overused. From there, they argued that students shouldn’t go to school year-round because it could strain their brains. To top it off, air conditioning was decades away, and city schools during summertime were miserable, half-empty ovens.

So by the turn of the century, urban districts had managed to cut about 60 schooldays from the most sweltering part of the year. Rural schools soon adopted the same pattern so they wouldn’t fall behind. Business folks obviously saw an opportunity here. The summer vacation biz soon ballooned into what is now one of the country’s largest billion-dollar industries.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

SECTIONS

arrow
LIVE SMARTER