Protesters in Portland and Seattle have reported unusual menstrual cycles after being exposed to tear gas used by law enforcement at Black Lives Matter demonstrations.
Although a link is possible, there has yet to be enough research into how tear gas affects reproductive systems to draw a definitive conclusion. Still, dozens at or near demonstrations in the northwest cities, where tear gas has been used extensively, feel certain that being exposed to the chemicals caused them to have irregular periods.
A July report from Oregon Public Broadcasting cited 26 protesters who say that their abnormal cycles, including getting periods multiple times in a month, are the result of being exposed to tear gas in Portland over the last two months. Seattle’s KUOW published a report Friday which recently interviewed 12 others with similar experiences linked to the Seattle Police Department’s use of tear gas at protests.
Research into the effects of tear gas on female sex hormones and reproductive systems is limited at best, due in part to their history of being developed as chemical weapons.
“The reason why there is no data about this is that these chemicals started out as agents of war and were studied — if at all — in a male population,” Seattle gynecologist Dr. Emily Norland told KUOW. “In medicine, we look to studies in order to understand the causal relationship of an exposure to an effect.”
Some evidence suggests that a causal relationship is at least plausible. The government of Chile banned chlorobenzylidene malononitrile, the most common form of tear gas often known as “CS gas,” from being used on protesters in 2011 after researchers in the country raised concerns that it could be responsible for miscarriages.
An alternative explanation for the irregular periods experienced by those exposed to tear gas could be high levels of stress, since research has established a relationship between the stress hormone cortisol and menstruation.
Regardless, the role of tear gas in causing many other symptoms is not in dispute. The most common immediate effects are unpleasant but largely temporary, such as burning or tearing eyes and blurred vision, nausea or vomiting, drooling and shortness of breath.
Potentially long-term damage has also been noted, including making people more susceptible to certain viral infections. High exposure can cause serious symptoms, potentially up to and including “immediate death due to severe chemical burns to the throat and lungs,” or “respiratory failure possibly resulting in death,” according to the Centers for Disease Control and Prevention (CDC).
While U.S. law enforcement officers continue to use the chemical weapons, referring to them as “riot control agents,” on domestic Black Lives Matter protesters, they have been banned for use in international warfare under the Chemical Weapons Convention since 1997.
“Governments that are at war are not terribly concerned for the most part, until held accountable by outside entities, with the effects that they have on people that they’re gassing,” said Norland. “And so this use of wartime agents against a citizenry — that was never the way these things were designed.”
Newsweek reached out to the CDC for comment.