Noxious History of School Bus Yellow

The yellow of a school bus is a color that conjures emotions. Developed to keep kids safe, this yellow and its commercial production have hazardous qualities that often go unmentioned. This broadcast, we’re going to learn the tale of how one man standardized school transportation, and the hidden cost behind that effort. This is the story of “School Bus Yellow.”

In the 1930’s, a doctor by the name of Frank Cyr wanted to implement standards for school transportation. During this period, the end of the great depression, kids were brought into school by all sorts of vehicles, including wagons, trucks, and buses. Cyr wanted to incorporate a standard color that improved visibility of these vehicles there by differentiating them from other traffic.

By 1939, he’d organized a safety conference (funded by the Rockerfeller foundation). This need for a safety standard eventually led the attendees to settle on the bold yellow that we know today as “National School Bus Glossy Yellow.”

In 1972, Minnesota was the last state to adopt the color for their busses. By 1974, all school busses in the United States were painted “School Bus Glossy Yellow.”

The reality of “School Bus Glossy Yellow” isn’t as cheery as it’s name would imply, however. The yellow had a different name before it was rebranded: “School Bus Chrome.”

Now, you might be asking yourself, “Isn’t chrome silverish?” and you’re right! The chrome nomenclature comes from the fact that this is a chromate paint. Chrome is a carcinogen, or as all my paint tubes like to say “This product contains a known carcinogen to the state of California.” Not only that, but chrome yellow is a lead chromate -- emphasis on the lead.

Lead is most dangerous to children, which is the dark irony of this whole story. Using carcinogens to keep kids safe. Children weren’t the only ones at risk, however. With national regulations requiring busses to be painted this particular shade, thousands of busses, new and old, had to be painted. The painters of these buses were the ones with the highest risk of lead exposure.

The effects of lead based paint on those who work with it have been studied since antiquity, and chromium-based yellow is often the worst of the bunch. In a 2018 article published on the Hematology Analysis of Lead Exposure on Painting Workers from Automobile Painting Industries in Karasak, Bandung, researchers discovered that yellow-chrome exposed workers to the highest amounts of lead, more than the next highest, grey. To account for natural accumulation of lead from the environment, they also maintained a control group consisting of non-painters. This control group had ⅓ of the content of lead in their body.

Lead poisoning is most often caused by ingestion. It enters the bloodstream, either through the stomach or lungs -- which is what makes spray-on paint such a hazard. In children, lead poisoning can result in developmental delays, learning disabilities, weight loss, seizures, and pica. In adults, it can cause mood disorders, memory problems, joint pain, headaches, and miscarriages.

Like I mentioned earlier, all busses were painted “National School Bus Glossy Yellow” by 1974. Regulated into the standard across the nation. The color offered protection to children from the hazards of the road, but exposed countless painters to the leaded pigment. Four years later, in 1978, all lead-based paint was banned -- ending the federal career of chrome yellow. From then on, busses would be painted with a less hazards yellow that was the same hue, just probably less opaque and more expensive. It’s kind of strange how the choice between a leaded pigment and a non-leaded one is made based off how many coats of paint it would take.

The federal ban did not quite extinguishing the hazard. With no recall, all those painted busses remained on the road, like all the other lead-painted cars at the time. And all the houses. And products. It really makes you wonder just how many things out there could be covered in lead -- but I’ll get into that next time.