Scientists urge caution after a carcinogen is detected in water in fire-stricken areas
Utilities in both the Eaton and Palisades fire burn scars have reported detecting the carcinogen benzene in parts of their water systems. State regulators have recommended the utilities issue “do not drink” and “do not boil” notices, which still permit residents to use the water for showers, handwashing, laundry and other daily activities.The state said the order attempts to balance safety with the need for usable water, while some scientists warned that using the water, even for purposes other than drinking or cooking, could pose a risk.Studies have linked long-term exposure to benzene through inhalation or ingestion to the development of blood cancers like leukemia. Research has also found long-term exposure can result in anemia, which can leave patients feeling weak and tired; a low white blood cell count, which debilitates the immune system; and a low platelet count, which leads to excessive bleeding and bruising.So far, two of Altadena’s three customer-owned water utilities have detected the carcinogen.Lincoln Avenue Water Co. said it has taken over 350 samples, and — out of the 296 samples analyzed so far in results posted on the California State Water Resources Control Board’s website — 30 had contamination above the state’s maximum allowed level, with concentrations as high as 31 times the allowed level. Rubio Cañon Land & Water Assn. said it has taken over 150 samples. Out of the 100 posted so far, six had contamination above the state limit, as high as 190 times the allowable level.Both Lincoln Avenue and Rubio Cañon posted a list of affected streets on their websites.Las Flores Water Co. — whose infrastructure suffered significant damage and has not been able to restore water pressure to large swaths of its customers, let alone begin comprehensive testing — did not immediately respond to a request for comment.The Los Angeles Department of Water and Power, the water utility responsible for most of the affected area of the Palisades, said it had detected benzene. However, it has not listed affected streets in its “do not drink” notice, nor has any of its testing data been posted on the California State Water Resources Control Board’s website yet, unlike Rubio Cañon and Lincoln Avenue.The LADWP said it was working on an online dashboard to help customers understand its testing data. The utility tested water at 276 sites and originally found 14 where the amount of benzene exceeded allowable limits. However, since then, the LADWP has been able to reduce the number of high benzene sites to eight by flushing water through the system.The allowable limits of contaminants in drinking water are set based on the risks posed by daily exposure over decades. Scientists said much less is known about the potential health implications for extreme, short-term exposure.It is unclear whether, or how many, currently undamaged and inhabited homes may be running water contaminated by benzene and at what level.Benzene is a common chemical in many materials found in and around houses, including in wood products, plastics, paints and gasoline. As these materials burn, benzene enters the smoke. And if water systems lose pressure and begin to completely drain, fire hydrants that were left open and broken connections at destroyed homes can suck smoke into the pipes to fill the void in the system.On Jan. 8, the three customer-owned private water utilities in Altadena (Lincoln Avenue, Rubio Cañon, and Las Flores) issued “do not use” orders — the most restrictive level of drinking-water-use notices. With no idea what contaminants could be in the water, they advised residents to avoid tap water altogether.The same day, the LADWP issued a “boil water” notice, which allowed residents to still drink the water if boiled, although the region remained under evacuation orders.The “boil water” notice is the least restrictive of the four drinking notices. It’s designed to protect against pathogens — like viruses and bacteria — that have contaminated the water supply but can be neutralized with high heat. The next level, a “do not drink” notice, is for contaminants that are dangerous to ingest even if they’re boiled.The combined “do not drink” and “do not boil” notice is for contaminants dangerous not only to ingest, but also to inhale as particles that can enter the air when boiled. Finally, the “do not use” notice is used when the potential contaminants are unknown or pose a danger when they contact the skin.The initial warnings issued on Jan. 8 were precautionary. At the time, no benzene or other contaminants had been detected. But public health officials and utilities were acting out of an abundance of caution given that in the aftermath of other urban wildfires — including the Tubbs fire and the Camp fire in Northern California and fires in Colorado and Hawaii — where benzene had been detected in water supplies.On Jan. 10, LADWP upgraded the notice to “do not drink,” advising against drinking the water even if boiled. And by the end of the following week, Lincoln Avenue and Rubio Cañon, on the advice of state regulators at the Division of Drinking Water, relaxed their notices to “do not drink” and “do not boil,” allowing residents to use the water for showers and other uses. Eaton and Palisades fires The devastating fires killed at least 28 people, destroying and damaging more than 18,000 buildings valued at more than $275 billion and leaving a burn zone 2½ times the size of Manhattan. While the current orders allow residents to use the water in some capacity, scientists say benzene can also enter the body through direct contact with the skin (though the amount absorbed compared to inhalation and ingestion is typically much lower).How residents use tap water makes a difference for their risk, experts say. For example: washing hands with cold water doesn’t create much risk for benzene exposure, said Gina Solomon, chief of the Division of Occupational, Environmental and Climate Medicine at UC San Francisco. On the other hand, taking a long, hot bath — especially with a rash or unhealed wound — means a more significant risk for absorption of the chemical.For this reason, the LADWP, Rubio Cañon and Lincoln Avenue all advise residents to limit hot water use, limit shower and bathing time, use the air-dry setting on dishwashers, avoid using clothes dryers and wash clothes with cold water.That said, the science isn’t fully settled. Researchers only really identified benzene as a prominent post-wildfire drinking water contaminant after the 2017 Tubbs fire, and some scientists said that not enough research has been conducted to confidently determine what household water uses are high risk and which aren’t.“Right now, there’s no chemical modeling, mathematical modeling or any exposure assessments that have been conducted to determine the answers to [these] questions,” said Andrew Whelton, a professor of civil environmental engineering at Purdue University and a leading researcher in the field of postfire water safety.California policy uses benzene as a sort of benchmark for contamination as a whole. The state requires utilities to test for bacteria and benzene contamination, arguing that benzene is a good indicator of whether other contaminants may be present.But Whelton and others emphatically argue that this assumption is not supported by the evidence. In previous fires, they point out, other known carcinogens in the same family as benzene, called volatile organic compounds (VOCs), have been found in water systems even when benzene was not present.The LADWP, Rubio Cañon and Lincoln Avenue all said they’re testing not just for benzene, but also for the full EPA-recommended suite of VOCs, including dangerous chemicals found after the Tubbs and Camp fires.In the meantime, experts advise that before using tap water, anyone in the burn scars should turn on all the faucets and water fixtures in their home and let them run for at least 10 to 15 minutes to flush out the system.Experts also cautioned that, while residents might seek at-home water-testing kits and filtration systems for extra peace of mind, most kits do not test for all prominent wildfire contaminants, and filtration cannot guarantee safe water if the contamination level is unknown.The utilities in Pacific Palisades and Altadena all said they were working as quickly as possible to restore drinking water without compromising on safety. With the detection of benzene, none could predict when they would be able to lift the “do not drink” and “do not boil” notices.
While residents in the Palisades and Eaton fire areas can use tap water for some limited purposes, the detection of a carcinogen in the systems can pose some risks.
Utilities in both the Eaton and Palisades fire burn scars have reported detecting the carcinogen benzene in parts of their water systems. State regulators have recommended the utilities issue “do not drink” and “do not boil” notices, which still permit residents to use the water for showers, handwashing, laundry and other daily activities.
The state said the order attempts to balance safety with the need for usable water, while some scientists warned that using the water, even for purposes other than drinking or cooking, could pose a risk.
Studies have linked long-term exposure to benzene through inhalation or ingestion to the development of blood cancers like leukemia. Research has also found long-term exposure can result in anemia, which can leave patients feeling weak and tired; a low white blood cell count, which debilitates the immune system; and a low platelet count, which leads to excessive bleeding and bruising.
So far, two of Altadena’s three customer-owned water utilities have detected the carcinogen.
Lincoln Avenue Water Co. said it has taken over 350 samples, and — out of the 296 samples analyzed so far in results posted on the California State Water Resources Control Board’s website — 30 had contamination above the state’s maximum allowed level, with concentrations as high as 31 times the allowed level. Rubio Cañon Land & Water Assn. said it has taken over 150 samples. Out of the 100 posted so far, six had contamination above the state limit, as high as 190 times the allowable level.
Both Lincoln Avenue and Rubio Cañon posted a list of affected streets on their websites.
Las Flores Water Co. — whose infrastructure suffered significant damage and has not been able to restore water pressure to large swaths of its customers, let alone begin comprehensive testing — did not immediately respond to a request for comment.
The Los Angeles Department of Water and Power, the water utility responsible for most of the affected area of the Palisades, said it had detected benzene. However, it has not listed affected streets in its “do not drink” notice, nor has any of its testing data been posted on the California State Water Resources Control Board’s website yet, unlike Rubio Cañon and Lincoln Avenue.
The LADWP said it was working on an online dashboard to help customers understand its testing data. The utility tested water at 276 sites and originally found 14 where the amount of benzene exceeded allowable limits. However, since then, the LADWP has been able to reduce the number of high benzene sites to eight by flushing water through the system.
The allowable limits of contaminants in drinking water are set based on the risks posed by daily exposure over decades. Scientists said much less is known about the potential health implications for extreme, short-term exposure.
It is unclear whether, or how many, currently undamaged and inhabited homes may be running water contaminated by benzene and at what level.
Benzene is a common chemical in many materials found in and around houses, including in wood products, plastics, paints and gasoline. As these materials burn, benzene enters the smoke. And if water systems lose pressure and begin to completely drain, fire hydrants that were left open and broken connections at destroyed homes can suck smoke into the pipes to fill the void in the system.
On Jan. 8, the three customer-owned private water utilities in Altadena (Lincoln Avenue, Rubio Cañon, and Las Flores) issued “do not use” orders — the most restrictive level of drinking-water-use notices. With no idea what contaminants could be in the water, they advised residents to avoid tap water altogether.
The same day, the LADWP issued a “boil water” notice, which allowed residents to still drink the water if boiled, although the region remained under evacuation orders.
The “boil water” notice is the least restrictive of the four drinking notices. It’s designed to protect against pathogens — like viruses and bacteria — that have contaminated the water supply but can be neutralized with high heat. The next level, a “do not drink” notice, is for contaminants that are dangerous to ingest even if they’re boiled.
The combined “do not drink” and “do not boil” notice is for contaminants dangerous not only to ingest, but also to inhale as particles that can enter the air when boiled. Finally, the “do not use” notice is used when the potential contaminants are unknown or pose a danger when they contact the skin.
The initial warnings issued on Jan. 8 were precautionary. At the time, no benzene or other contaminants had been detected. But public health officials and utilities were acting out of an abundance of caution given that in the aftermath of other urban wildfires — including the Tubbs fire and the Camp fire in Northern California and fires in Colorado and Hawaii — where benzene had been detected in water supplies.
On Jan. 10, LADWP upgraded the notice to “do not drink,” advising against drinking the water even if boiled. And by the end of the following week, Lincoln Avenue and Rubio Cañon, on the advice of state regulators at the Division of Drinking Water, relaxed their notices to “do not drink” and “do not boil,” allowing residents to use the water for showers and other uses.
Eaton and Palisades fires
The devastating fires killed at least 28 people, destroying and damaging more than 18,000 buildings valued at more than $275 billion and leaving a burn zone 2½ times the size of Manhattan.
While the current orders allow residents to use the water in some capacity, scientists say benzene can also enter the body through direct contact with the skin (though the amount absorbed compared to inhalation and ingestion is typically much lower).
How residents use tap water makes a difference for their risk, experts say. For example: washing hands with cold water doesn’t create much risk for benzene exposure, said Gina Solomon, chief of the Division of Occupational, Environmental and Climate Medicine at UC San Francisco. On the other hand, taking a long, hot bath — especially with a rash or unhealed wound — means a more significant risk for absorption of the chemical.
For this reason, the LADWP, Rubio Cañon and Lincoln Avenue all advise residents to limit hot water use, limit shower and bathing time, use the air-dry setting on dishwashers, avoid using clothes dryers and wash clothes with cold water.
That said, the science isn’t fully settled. Researchers only really identified benzene as a prominent post-wildfire drinking water contaminant after the 2017 Tubbs fire, and some scientists said that not enough research has been conducted to confidently determine what household water uses are high risk and which aren’t.
“Right now, there’s no chemical modeling, mathematical modeling or any exposure assessments that have been conducted to determine the answers to [these] questions,” said Andrew Whelton, a professor of civil environmental engineering at Purdue University and a leading researcher in the field of postfire water safety.
California policy uses benzene as a sort of benchmark for contamination as a whole. The state requires utilities to test for bacteria and benzene contamination, arguing that benzene is a good indicator of whether other contaminants may be present.
But Whelton and others emphatically argue that this assumption is not supported by the evidence. In previous fires, they point out, other known carcinogens in the same family as benzene, called volatile organic compounds (VOCs), have been found in water systems even when benzene was not present.
The LADWP, Rubio Cañon and Lincoln Avenue all said they’re testing not just for benzene, but also for the full EPA-recommended suite of VOCs, including dangerous chemicals found after the Tubbs and Camp fires.
In the meantime, experts advise that before using tap water, anyone in the burn scars should turn on all the faucets and water fixtures in their home and let them run for at least 10 to 15 minutes to flush out the system.
Experts also cautioned that, while residents might seek at-home water-testing kits and filtration systems for extra peace of mind, most kits do not test for all prominent wildfire contaminants, and filtration cannot guarantee safe water if the contamination level is unknown.
The utilities in Pacific Palisades and Altadena all said they were working as quickly as possible to restore drinking water without compromising on safety. With the detection of benzene, none could predict when they would be able to lift the “do not drink” and “do not boil” notices.