Painted Warnings: Hanford's Hand-Lettered Radiation Signs

Before there was a standard radiation symbol, the warnings at the Hanford Site in Washington State were painted by hand. A panel in the Health Physics Exhibit at the B Reactor — part of Manhattan Project National Historical Park — tells the story of the sign painters who made them.

The Painted Warnings panel in the Health Physics Exhibit. Image credits are on the panel itself.

Health physics, and why signs mattered

The exhibit is about health physics: the science of protecting people and the environment from the harmful effects of radiation. The Manhattan Project brought a new kind of workplace hazard, one that could not be seen, heard or smelled. A worker had to be told, clearly and every time, where the danger was — and at Hanford that job fell to the Sign Shop.

The sign shop

Every sign was a set of small decisions — which lettering, whether to add an exclamation point, whether two colours would catch the eye faster than one — and each one mattered, because the sign was what stood between a coworker and an exposure.

The painters left their marks. It was possible to tell who had made a sign from the technique: some dotted an i with a diamond, others with a circle.

From octagons to the trefoil

Hand-painted safety signs were everywhere on the site, covering every kind of industrial hazard. Before the yellow-and-magenta radiation trefoil became the standard warning, Hanford used octagonal signs — one on the panel, shaped like a stop sign, reads "Radiation danger zone, keep out." Another shows a worker holding a sign that says "Danger, overhead work."

Those painters were at the start of something that now reaches every nuclear workplace in the world: standardized signs that warn of danger the same way wherever they are posted.

What the panel shows

• A black-and-white photograph of the paint and print shop, its walls covered in signs and illustrations.
• Two round inset photographs of a woman and a man seated at easels.
• The two warning signs above, held up or posted on site.

Visiting

The B Reactor can be visited in person only on guided tours offered by the U.S. Department of Energy.

Sources

Written from "B Reactor Health Physics Exhibit: Painted Warnings," Manhattan Project National Historical Park, National Park Service; a work of the United States government in the public domain.