The county is pushing back on university researchers’ reports of toxic or lethal gases spreading into South Bay communities from the polluted Tijuana River that triggered widespread panic.
County hazardous waste experts say instruments used by San Diego State University researchers likely delivered falsely high positive results for the presence of the toxic gas hydrogen cyanide, a byproduct of plastics, nylon and fumigants manufacturing, around the Tijuana River Valley. When news of high hydrogen cyanide levels was first reported, it triggered some South Bay schools to cancel outdoor activities and San Diego Congressional delegates to call again for a federal state of emergency due to the pollution.
But the county says: There’s no reason to be alarmed right now.
“The county has not received any data that as of now indicates a public safety concern,” San Diego County Supervisor Nora Vargas said at a press conference Tuesday morning. “Our county experts worked side by side with researchers… and found there were no significant hydrogen cyanide readings. The levels are not posing a public health hazard.”
The hydrogen cyanide readings that triggered the public health scare come from San Diego State University. The researchers in that group did not respond to a request for comment. Those researchers, along with a group at University of California-San Diego, have also reported high levels of hydrogen sulfide, a colorless gas with a rotten egg smell commonly associated with raw sewage.
The problem, according to Leon Wirschem with the county Department of Environmental Health and Quality, is that certain air quality monitoring instruments that measure toxins in the air can show falsely high readings of hydrogen cyanide even when it’s barely present. That happens when instruments are measuring air that also contains hydrogen sulfide, he said, a phenomenon called cross-sensitivity.
Kim Prather, an atmospheric scientist from University of California-San Diego’s Scripps Institution of Oceanography whose lab is also taking measurements in the area, said that doesn’t explain the dangerous state of South Bay’s air.
“We have sophisticated equipment and we are continuing to do these measurements. We cannot get distracted,” Prather said. “The public needs help and truth and we will get there.”
Prather took to the social media platform X to challenge Vargas’ statements Tuesday that South Bay residents should have nothing to fear and can return to their normal activities.
“I have a well-established track record in air measurements for 32 years. It is deeply disturbing to see a politician who is not an air expert try and smear the reputation and efforts of those of us who are the experts working around the clock trying to help this community. Why?,” Prather wrote.
In her tweets, Prather referred only to hydrogen sulfide readings, the gas that indicates sewage, which her team of researchers have been recording in the area. Her team reportedly suffered sleepless nights in South Bay while working on the monitoring project. Prather decided to move team members to hotels, which became news.
So far no entity, neither Prather nor SDSU have released their air quality data to Voice of San Diego for review. The county shared air sample results taken Monday. Saturn Boulevard delivered the highest reading for hydrogen cyanide at 25 parts per million (meaning 25 of 1 million particles of air) which is below any immediate life and safety threshold, according to county officials. The county said that level of hydrogen cyanide didn’t stick around for long, which is taken into account when determining public safety threats.
Vargas said she requested the U.S. Centers for Disease Control and Prevention and the California Department of Public Health investigate the health impacts of the cross-border pollution. The goal is to identify a link between pollution and health issues, she said.
Interim Public Health Officer Anikita Kadakia said the human nose is very sensitive to hydrogen sulfide, the sewer gas, which can detect levels far below dangerous thresholds.
“Hydrogen sulfide can lead to real health symptoms for some people like nausea and headaches,” she said. “I’m asking the true regional experts on this subject, the San Diego Air Pollution Control District, which already has sensors in place to provide additional support for the South (Bay) community.”
On Sunday, the Air Pollution Control District said people in South Bay who notice the odors, the elderly and children should stay indoors due to the combination of smell and extreme heat. Compounds associated with those odors could cause adverse health effects, the district said.
She asked the regional air quality district to hire additional experts, distribute air purifiers based on air sensor data and vulnerability of households, and develop a public notification plan similar to how the county now issues beach water quality notifications.
“The county has not received any data that as of now indicates a public safety concern,” San Diego County Supervisor Nora Vargas said at a press conference Tuesday morning. “Our county experts worked side by side with researchers… and found there were no significant hydrogen cyanide readings. The levels are not posing a public health hazard.”
We need an outside, independent, expert source to go in and do the testing. As we have seen so many times before, anytime government tells you something, “Trust, but verify.”
It is extremely disconcerting to hear a politician making these absurd claims. I am a 3rd generation oil and gas worker with right at 30 years in the field so far. My father retired with 50 years, just for some background. The number one thing that will kill you in the field without hesistation is Hydrogen Sulfide. When this politician, Vargas, quotes out “Hydrogen sulfide can lead to real health symptoms for some people like nausea and headaches,” she needs to get real. The reality is hydrogen sulfide can lead to real health symptoms like unconsciousness and death, even at relatively low concentrations. H2S is much like a metabolic poison. It steals your oxygen, disrupts the creation ATP and essentially chokes the life out of you and your high oxygen consuming organs, such as the brain and heart. This is known as the knockout effect, for those interested. Just ask OSHA or NIOSH. The facts are, OSHA’s legal airborne permissible exposure limit (PEL) is 20 ppm not to be exceeded at any time, and 50 ppm as a maximum peak, not to be exceeded during any 10-minute work period. NIOSH’s recommended airborne exposure limit (REL) is 10 ppm, which should not be exceeded during any 10-minute work period. Detailed stats can be found on OSHAs website. Hydrogen sulfide attacks the olfactory system in living organisms and will absolutely paralyze the olfactory nerve making it undetectable at higher levels. That’s what makes these lower levels so dangerous. If we smell H2S in the O&G field, it is an immediate Evac emergency to a designated muster point as one can not detect these higher levels off of sense of smell that can and will kill you.Hence having to carry an H2S monitor on our upper body every single day. As far as cross sensitivity goes and the claims about such, hydrogen sulfide has a very unique molecular structure when it comes to being detected. It is the only gas that is not able to be picked up by Optical Gas Imagery sensors. Even attempting the use of quantum well infrared photo detector, or QWIP, (the most expensive/sensitive type of imaging sensor) will yield no results. The usefulness of being able to detect H2S with imaging equipment goes beyond measure and if there was a way to do so, the oil and gas field would absolutely have it. This makes me seriously question the statement being made about the cross sensitivity from H2S to Hydrogen Cyanide as the equipment made to detect these elements are made specifically to detect these exact elements and not carry over with cross contamination, as these are mistakes that can and will kill you. These politicians obviously have ZERO experience with any of this type of safety hazard and instead of choosing to safeguard the public, they attempt to downplay an expert with over 3 decades of environmental air monitoring experience. This just absolutely floors me. Never in my life have I heard someone (or a group of someones…these politicians) make such obtuse statements about hydrogen sulfide. Please do not believe what these politicians are trying to shill to you. Stick to what the Subject Matter Experts are trying to warn you about. Your very life may just depend on it. Prather asks “Why?” Money, that’s why. Property values, business losses, stale development due to public outcry…the list goes on, but it all stems from fear of loss of the mighty dollar. So much money has already been spent (let’s just pick IB for instance) in revamping and cleaning up, making things look new and nice…new housing, new businesses, fresh hotel remodels, etc. An outcry like this about the safety of people in the area will surely put a significant dent in the ability to capitalize on these funds that have been spent to attract even more people, therefore attracting their pocket books as well. Money and greed, it’s a story as old as time, however sad it may be. Do your own research, safeguard yourself and protect your families. These city “leaders” ARE NOT going to do that for you.
Mixed feelings about this. On one hand, it’s very odd to hear a local politician make any references to instrument sensitivity unless they have a background in the hard sciences, which makes me skeptical. On the other hand, Prather is not infallible either. Anyone remember her significant hand in the COVID surfing bans? She theorized the virus could be aerosolized in seafoam and travel over water much more easily and much further. Correct me if I’m wrong, but that turned out to not be the case and in hindsight was somewhat alarmist.
The university and SDAPCD measurements and ambient air quality standards are in ppb, the OSHA standards are ppm (1,000) times higher. The County personnel are talking about the OSHA standards and the researchers are talking about ambient air quality standards. Health vs. Safety. This is a good reason to be thankful for our WWTP and other industrial workers as they are only protected by the safety standards where as we (public) are protected by the much more stringent health standards.
you should publicly shame people in posts like this to generate clicks, the pollution stories get boosted by local media way more
I bet this politicans Vargas who claims “There’s No Toxic Gas Concern in Tijuana River Valley” Is the same politician who will claim that we can’t have gas stoves due to the toxic gas that kills little children.