That same month, the American Civil Liberties Union of Southern California issued a sobering report on pepper spray, which had been legalized for police use in October 1992. By May 31, 1995, California law-enforcement officers had used it nearly 16,000 times, roughly 24 times per day. Twenty-six people had died -- not including Williams -- giving pepper-spray victims a 1-in-600 chance at death.
By October 1995, the San Francisco Police Department had updated its use-of-force policy, which details when and how pepper should be used. However, it appears that SFPD didn't follow that policy six months later when officers picked up an incoherent Mark Garcia, then pepper-sprayed and hog-tied him. He died the next day, after suffering two massive heart attacks.
Since then, no one has died in SFPD custody following the use of pepper spray, according to Officer Albie Esparza. But with a wave of police pepper-spray attacks on Occupy Wall Street protests in Davis and across the United States, could it happen again?
"Davis was an eye-opener," said Sean Seamans, a camper at Occupy San Francisco. "As with all 'non-lethal' items, as long as you put the 'non' in front, it gives you the excuse to use it liberally. And if you have asthma or respiratory issues, it puts lives at risk."
Pepper spray, sometimes known by its formal name oleoresin capsicum, is a concentrated version of the substances that give spicy peppers their heat. In the human body, these substances release a brain-signaling compound called Substance P. Among other things, Substance P causes the airways to close, triggering uncontrollable coughing and making it difficult to breathe.
"Occupational Health Services, Inc., [a private research facility in Kansas City, Missouri], reported that because [oleoresin capsicum] caused the subject's breathing passages to swell and constrict, the use of OC on persons with pre-existing respiratory conditions such as asthma could, in rare instances, cause death," according to the ACLU report.
Local police don't see it that way. "People do not die from pepper spray itself. There are other, associated factors," such as alcohol or drug use, as well as the "hog-tie" or hobble restraint, Esparza said. "The pepper spray we use is nothing more than Tabasco sauce in a canister."
Hmm. According to Tabasco's website, its spiciest sauce -- made of habanero peppers -- is a bit more than 7,000 on the Scoville scale, used to measure capsaicin's potency. Meanwhile, U.S.-grade pepper spray rates somewhere above 2 million on the Scoville scale, according to Scientific American.
While the ACLU report called for better tracking and oversight into police use of pepper spray, other agencies went further. The Ella Baker Center for Human Rights -- then based in San Francisco, demanded a moratorium on the practice, in part because of its potential lethality. No police departments took them up on the demand, according to Ella Baker spokesman Abel Habtegeorgis.
"You're quicker to use things like that because you're told that this is not lethal, when in all actuality, your haste in using them can prove to be deadly," Habtegeorgis said. "If police are going to have these weapons that can be deadly, they should use the same precaution they would use for a gun."
Eight Headwaters Forest demonstrators won a victory over the police use of pepper spray in 2005, when a Humboldt County judge ruled that officers used excessive force in swabbing the stuff into protester's eyes. However, the precedent only applies within that county, according to Headwaters Forest Defense spokeswoman Karen Pickett.
"It's way too limited," Pickett said. Although the Headwaters trial focused on pepper spray's potential to cause permanent eye damage, some court evidence showed that it can be fatal when people have respiratory problems.
No Occupy Wall Street demonstrators have died after being pepper-sprayed -- and SFPD hasn't used it on local protesters, according to Esparza and Seamans.
During a recent raid, "I had eight officers on me at one time, and pepper spray was threatened," Seamans said. He keeps goggles and a respirator at hand, just in case.
"Officers don't like to use force unless we have to," Esparza said. "But when someone's given a lawful order, it's against the law for them not to follow those orders. If you do what the officer tells you, there's no need for further escalation."