For hundreds of years, lighthouse keepers were essential to ensuring maritime safety across the United States, tending to the storied structures and helping ships to navigate through treacherous waters.

But while they kept others from danger, including here in the Columbia-Pacific region, theirs was a job that came with many occupational hazards. Some have been well-documented. Others, like health effects caused by mercury exposure, are still being investigated.

Lightning was an early concern for architects of colonial lighthouses on the East Coast. Given that they were often the tallest structures on the landscape and contained at least some metal, lighthouse towers could be prime targets in a raging storm.

The Boston Light, one of North America’s oldest, located on Little Brewster Island in Boston Harbor, is an example.

Lightning and fire

As historian Elinor De Wire explains in the book “Guardians of the Lights: Stories of U.S. Lighthouse Keepers,” the community around Boston Light was initially against installing a lightning rod due to their religious beliefs about interfering with the divine.

However, “after the lighthouse was struck and damaged by lightning some twelve times in ten years, twice setting it on fire, a lightning rod was installed.”

Prior to electrification, fire was another serious issue for keepers using oil lamps and pressurized gas tanks. This was especially true in the early years of U.S. lighthouse-keeping, as many structures were made entirely of wood.

De Wire explains that wood towers “were also vulnerable to fire due to the many combustible materials used in the lighthouse lantern … Surprisingly, even the optic itself was a danger, since its powerful lens panels could focus sunlight into an intense beam capable of igniting dry grass or dead trees.”

Lighthouse lenses often faced the wrath of the environment around them. Tillamook Rock Lighthouse, located a little more than a mile off the Oregon Coast between Seaside and Cannon Beach, was particularly exposed.

As author Debra Baldwin describes in “Tillamook Rock Lighthouse,” part of Arcadia Publishing’s “Images of America” series, “The lighthouse roof was continually being crushed in or pierced through, letting in seawater that decimated the living quarters below while almost drowning the keepers.”

Annual reports from the U.S. Lighthouse Board consistently cited towering waves and massive boulders hurling themselves against the side of the tower.

A piece of Tillamook Rock now sits in the Columbia River Maritime Museum’s collection after being thrown into the tower during a 1912 storm. The keeper on duty at the time took the opportunity to recreate the lighthouse on a piece of the rock upon which it sat.

Lenses in mercury

In the 1890s, Leon Bourdelles designed a structure that would allow lighthouse lenses, which could weigh thousands of pounds, to float on a bed of mercury that was a fraction of the lenses’ weight.

This was essential to turning the lighthouse lens on its clockwork mechanism that created the signature light pattern identifying each tower.

As Theresa Levitt describes in “A Short Bright Flash: Augustin Fresnel and the Birth of the Modern Lighthouse,” “The system was now essentially frictionless, and the slightest touch could turn the largest lenses.”

But, she writes, there was little awareness of the element’s toxicity at the time. Keepers were likely unconcerned with the amount of time they spent cleaning and topping up the lens’ mercury bath.

However, as the University of Calgary’s Michaela Walter writes, “Chronic low-dose exposure can affect the nervous system primarily by causing a fine tremor in the hands … non-specific behavioral effects, damage to short- and long-term memory, insomnia, decreased ability to concentrate, dizziness, and fluctuating mood changes which includes depression.”

Many historians have cited stories from community members about keepers’ and their families’ mental health slowly declining.

Although this was initially attributed to the isolation and loneliness of the job, some now think there may be a connection to the mercury they were exposed to in their work.

Researchers are still investigating the prominence of mercury as a hazard in lighthouse keeping.

Now, with the automation of lighthouses, it can be difficult to imagine what daily life was like for those early caretakers. Keepers persevered through many challenges, in a hazardous job that was also a lifeline for mariners.