The fluids used in hydraulic fracturing of oil wells in California contain dozens of chemicals that are hazardous to human health, including substances linked to cancer, reproductive harm and hormone disruption, an EWG analysis of state data shows.
Under a 2013 California law (SB 4) requiring disclosure of all chemicals used to boost production from oil wells by fracking or similar methods, drilling companies reported using 197 unique chemicals in 691 oil wells from December 2013 through February 2015. The fracking fluids typically contained two dozen or more different chemicals. EWG’s analysis1 found that they included:
- 15 listed under California’s Proposition 65 as known causes of cancer or reproductive harm
- 25 likely to contain impurities of Proposition 65-listed chemicals
- 5 that the European Union has associated with an increased risk of cancer
- 6 associated with reproductive harm
- 3 linked to clear evidence of hormone disruption
- 12 listed under the federal Clean Air Act as Hazardous Air Pollutants known to cause cancer or other harm
- 93 associated with harm to aquatic life.
California’s fracking disclosure law is the most comprehensive in the nation. The data in the reports submitted to the state’s oil and gas regulatory agency provide the most detailed accounting available of the chemical makeup of fracking fluids, at least for one state.
Fracking fluid is a mix of water, chemicals and sand that is pumped into underground shale rock formations under great pressure to free up trapped oil and gas. After a well is “treated” in this way, some of the fluid flows back to the surface, usually picking up additional chemicals that occur naturally in the shale. In California, most of the wastewater is disposed of in underground injection wells or in unlined pits, some of them dangerously close to potential sources of drinking or agricultural water. An earlier EWG analysis found that fracking wastewater contains numerous hazardous substances, some at levels much higher than state drinking water regulations allow (EWG 2015).
Nationwide, a recent U.S. Environmental Protection Agency report found nearly 700 fracking chemicals in use (EPA 2015a). But EPA relied on data from FracFocus. org, an industry-funded voluntary database that – unlike the California law – allows companies withhold information they consider trade secrets. FracFocus.org has repeatedly come under criticism for inaccuracies and lack of transparency (Hass et al 2012).
Comparing the state and EPA data shows that some of the most hazardous chemicals are used less often in California than nationwide, but the typical California job uses about twice as many distinct chemicals as the national average.2 And because fracking in California tends to use less water than in other states, the concentrations of chemicals in fracking fluids are sometimes higher (CCST 2015).
The new EWG analysis looks at what goes into the fracking fluid before it’s pumped into a well, revealing the likely origin of some contaminants in the wastewater and also the array of hazardous chemicals used, stored or transported at fracking sites. These chemicals have the potential to contaminate drinking water, air and soil, as well as to endanger the health of oilfield workers and people who live or work nearby. It is an industrial process that from beginning to end is a source of potential exposure to chemicals that are hazardous for people and the environment.
All citizens, and especially those living near fracking operations, have a right to understand the risks posed by fracking chemicals. In the absence of a moratorium or ban on fracking, California should make public safety its primary goal, not increasing the production of hydrocarbons. To accomplish this, state regulators should:
- assess whether less harmful alternatives can replace the toxic chemicals currently used;
- immediately halt the injection of wastewater into potential sources of drinking or agricultural water; and
- support recommendations for groundwater monitoring in oil and gas areas and properly enforce the model criteria developed under the disclosure law.
1 The 197 chemicals were compared to an EWG database drawn from 15 sources, including government agencies, industry panels and aca- demic institutions and Material Safety Data Sheets required by federal regulations. The tables in the Appendix provide the unique Chemical Abstracts Service Registry number for each chemical, which can be used to look up the safety data sheet.
2 It is unclear whether California fracking jobs actually use more unique chemicals or if the difference is because California’s disclosure law is more comprehensive.
Hydraulic fracturing: a risk to drinking water and air quality
The nationwide fracking boom has sparked rising concern about and research into the health risks of the chemicals used (Colborn 2011, Bolden 2015, Webb et al 2014, EPA 2015b). Fracking chemicals include known carcinogens, reproductive toxins and endocrine disruptors, and drillers use many new chemicals whose health effects are largely unknown (Souther et al 2014, Schnoor 2014, Stringfellow 2014). Disclosure of these hazardous or little-known chemicals is essential to inform the public, trace contamination and study the long-term effects on health and the environment.
The oil and gas industry has long maintained that fracking chemicals are not a threat to drinking water, but evidence to the contrary is growing.
- A 2011 investigation by EWG and Earthjustice revealed that more than 25 years ago, an EPA study concluded that chemicals used to frack a 4,000-foot-deep natural gas well in West Virginia contaminated an underground drinking water source (EWG 2011).
- In May 2015, a Penn State University study found a commonly used fracking chemical, known as 2BE3, in tap water from homes near fracked gas wells. The chemical is known to cause cancer in lab animals. Researchers said the contamination likely came either from a leak during drilling or a leaky wastewater pit (Llewellyn et al 2015).
- In June 2015, the EPA released a draft report that concluded, “there are above and below ground mechanisms by which hydraulic fracturing activities have the potential to impact drinking water resources.” The federal agency said it found no “widespread, systemic impacts” but did find “instances where one or more mechanisms led to impacts on drinking water resources, including contamination of drinking water wells.” EPA said that in 2013, about 6,800 sources of drinking water nationwide, serving more than 8.6 million people, were within one mile of a fracked well (EPA 2015b).
- A recent 2015 study of water supply wells in the Barnett Shale region of Texas found contamination from BTEX chemicals (benzene, toluene, ethylbenzene, xylene), chlorinated compounds and alcohols. Although the study, published in the journal Environmental Science & Technology, could not definitely link the contamination to hydraulic fracturing, chemicals used in the process were identified in hundreds of wells in the region (Hildenbrand et al 2015).
Researchers have also documented health hazards from air pollution for people living near fracking sites:
- A recent study by the Yale University School of Medicine found significantly more respiratory and skin symptoms among Pennsylvanians living within a kilometer of a fracking site than among those farther away (Rabinowitz et al 2014).
- Air samples near oil and gas production sites in six states found benzene, formaldehyde and other known carcinogens at levels far above federal health standards (Macey et al 2014, Coming Clean 2014).
- If inhaled, the crystalline silica sand used in fracking fluid can cause cancer or silicosis, an incurable scarring of the lungs (OSHA 2002).
Fracking has been used to increase production from California wells since at least 1953, but until recently the state’s oil and gas division did not keep records on fracking or even know where it was occurring (EWG 2012). Currently, fracking is used to produce about one-fifth of all oil in the state (CCST 2015). In 2013, mounting public concern about fracking’s health and environmental hazards pushed the state to adopt the most stringent regulations in the nation, including required notification of planned fracking jobs, disclosure of all chemicals added to fracking fluid4 and testing and reporting of chemicals in fracking wastewater.
However, recent revelations that the state illegally allowed disposal of oil and gas wastewater into potential sources of drinking water show that disclosure is not enough. EWG’s analysis reveals that because fracking is heavily dependent on the use of chemicals known to harm human health and the environment, it is by its very nature a toxic threat. California must go beyond ensuring the public’s right to know and take stronger steps to protect public health.
4 California lets companies apply to the oil and gas division for permis- sion to withhold the exact formula of some “trade secret” additives from the website accessible to the public, but those details must still be reported to the state and the chemical constituents of those addi- tives must be publicly disclosed.
California’s fracking disclosure law
Fracking has been used to stimulate production of oil and gas wells in California for more than 60 years amid an appalling lack of oversight and few rules. In 2012, the Division of Oil, Gas & Geothermal Resources, or DOGGR, admitted that it did not keep any records on fracking or even know where it was occurring (EWG 2012). Public concern about the health and environmental effects of fracking mounted, and in 2013 the California Legislature 4 California lets companies apply to the oil and gas division for permis- sion to withhold the exact formula of some “trade secret” additives from the website accessible to the public, but those details must still be reported to the state and the chemical constituents of those addi- tives must be publicly disclosed. passed Senate Bill 4, the most comprehensive fracking law in the nation. Governor Jerry Brown signed it into law on January 1, 2014.
The law requires drillers to apply for permits for any well activity used to stimulate greater production from a well, whether by fracking or acid. The application must include the location and time of the proposed well treatment, a list of all chemicals to be used, the source of the water used and a plan to monitor groundwater in the area for possible contamination. Notices of the proposed activities are publicly disclosed on the oil and gas division’s website (DOGGR 2015). Property owners near the site must also be notified within 30 days of the activity.
Within 60 days of completing a fracking operation, drillers must disclose the source and amount of water used and the chemicals in the fracking fluid. They must also disclose how much water was recovered, test the wastewater and report all chemicals detected. This information is publicly available in the Well Stimulation Public Disclosure Report, which is posted and regularly updated on the website (DOOGR 2015).
Thirteen states now have laws requiring the disclosure of chemicals used in fracking operations, but most allow the withholding of “trade secrets.” An additional 15 states have chemical disclosure rules that require reporting to FracFocus.org (FracFocus.org 2015), a website that is partly funded by the oil and gas industry. The reporting to that site is known to contain errors or have missing data (Konschink 2013). Trade secrets are allowed on FracFocus, preventing full transparency, and searching for data on the website is cumbersome.
California’s public disclosure program is not without flaws, but it is more useful than FracFocus. Unlike FracFocus, the California website makes it possible to easily search for multiple records and download all records for analysis. Even if drillers refuse to publicly disclose their fracking fluid formulas as “trade secrets,” they must disclose all chemicals used to the state agency, and that list must be made public (SB 4 2013). EWG’s analysis of the disclosures on the Division’s database from December 2013 to February 2015 also shows:
- Hydraulic fracturing is by far the most common type of well stimulation in California, but some wells are treated by “acid fracturing” or “matrix acidizing,” which involve injecting acids instead of a mix of water and chemicals. About 95 percent of the well treatments involved hydraulic fracturing, 4 percent were matrix acidizing and 1 percent acid fracturing.
- Nearly all of the more than 1,500 pre-fracking notices reported were for Kern County, although several were for operations in Fresno, Kings and Ventura counties. (Fracking is concentrated in those areas, but it is possible that chemicals could have impacts beyond those regions.)
- California operators used an average of 62,600 gallons of water for each fracking job. Added chemicals typically made up less than 2 percent of the fluid. Typically only 1-to-5 percent of the fluid was recovered for disposal or recycling.
In its first full year of operation, lax oversight of the disclosure program resulted in missing records and confusing inconsistencies in the information reported to the state (EWG 2015, White 2015). In early 2015, both EWG and the California legislature questioned the oil and gas division about the problems. The head of the division said it was working with drilling operators to help them understand the regulations and that the final regulations would be more specific. Changes in the final regulations included requiring operators to list specific chemicals to be tested in the recovered wastewater and to specify where they disposed of the wastewater. The final regulations for the disclosure program took effect on July 1, 2015.
The health hazards of fracking chemicals
Since January 2014, oil and gas companies in California have been required to report all chemicals used in fracking or other well stimulation methods to the Division of Oil, Gas and Geothermal Resources, which publishes these Well Stimulation Public Disclosure reports on its website. (The website includes reports on some wells treated in December 2013.) From these reports, EWG reviewed the chemicals listed under the Well Stimulation Fluid Information tab (DOGGR 2015).
Through February 2015, a total of 691 fracking jobs were reported, all for oil wells and nearly all in Kern County. These fracking jobs used 197 distinct chemicals – typically 25 to 30 chemicals for each operation. (See Appendices 1 and 2 for the complete list of 197 chemicals, how often they were used and a summary of their health effects.) They include:
After water, the second most commonly used ingredient in fracking fluid was sand – but not just any sand. Every fracking job in the state database used crystalline silica and calcined diatomaceous earth, which is largely composed of crystalline silica. If inhaled, airborne crystalline silica is a Proposition 65 carcinogen. Mining, transport, storage and use of these sands can result in hazardous air quality for miners, workers at fracking sites and people nearby (EWG 2015, NPR 2013).
About 90 percent of the fracking jobs reported using chemicals refined from crude oil known as petroleum distillates. Diesel fuel – the only chemical prohibited in fracking under the federal Safe Drinking Water Act – is a petroleum distillate. The U.S. EPA does not consider the two types of distillates reported in the state database to be diesel. However, one is listed by the European Union as carcinogenic, and the other is an acute inhalation hazard, has nervous system effects and is toxic to aquatic life. Petroleum distillates can contain traces of BTEX chemicals – benzene and ethylbenzene, both Proposition 65 carcinogens; toluene, a Proposition 65 reproductive toxin; and xylene, a hazardous air pollutant.
The fracking disclosure report lists 11 chemicals classified as aromatic hydrocarbons, including xylene, toluene, trimethylbenzene and naphthalene. Most have been linked to cancer, reproductive harm or hormone disruption. A recent study found that exposure to the BTEX chemicals, which are all aromatic hydrocarbons, may disrupt hormones even at exposure levels the EPA currently considers safe (Bolden et al, 2015). Although these chemicals were used less often – in about 2-to-5 percent of the fracking jobs reported – the levels of BTEX chemicals in EWG’s previous analysis of fracking wastewater were quite high (EWG 2015), suggesting that the wastewater may contain naturally occurring hydrocarbons from the petroleum deposits or shale formations.
Eight different biocides – chemicals that kill bacteria – are listed in the disclosures, with additives known as MIT5 and CMIT6 the most common. They are used to prevent the growth of bacteria that could clog or corrode the wells. They are poisonous by design, so it is not surprising that MIT and CMIT biocides are extremely toxic to aquatic life. In the environment, sunlight may break down biocides, but little is known about what happens to biocides after they are pumped down a well (Kahrilas et al 2014).
Glycol ethers and alcohols
The disclosure reports list 24 unique chemicals classified as glycol ethers or ethoxylated alcohols. Although many of them are ingredients in household cleaning products, they have been linked to health and environmental harms. Most of the alcohols are toxic to aquatic life and often contain as impurities ethylene oxide and 1,4 dioxane, both Proposition 65 carcinogens. Glycol ethers have been also linked to suspected endocrine disruption and reproductive harm in people.
Chemicals by category
Table 1 lists the categories of all reported fracking chemicals by use, how often each was used and examples of specific chemicals in that category.
Table 1. Types and examples of chemicals reported by California fracking jobs from December 2014 to February 2015, with percentage of jobs using each type.
|Chemical||Purpose||Percent of fracking jobs that reported using it||Example of specific chemicals|
|Proppant||Keeps fractures in the rock open for oil and gas to flow||100%||crystalline silica (frac sand) diatomaceous earth|
|Breaker||Reduces thickness of the fluid to release proppant into fractures. Allows fluid to flow after proppant has been added||100%||ammonium persulfate sodium chloride hemicellulase enzyme|
|Gelling Agent||Increases fluid thickness to suspend the proppant||97%||guar gum petroleum distillates ethylene glycol|
|Locks clays in the rock to keep pore spaces open||97%||magnesium chloride magnesium nitrate oxyaklylated amine quat|
|Inhibits growth of bacteria that reduce the amount of proppant carried||94%||methylisothiazolinone chloromethylisothiazolinone|
|Crosslinker||Maintain fluid viscosity||94%||sodium tetraborate vinylidene chloride/methyl acrylate copolymer|
|Scale inhibitor||Prevents mineral scale in pipes and in the rock||77%||ethylene glycol nitrilo methylene phosphonic acid phosphonic acid ammonium chloride|
|Iron Control||Prevents build-up of metal oxides||15%||citric acid|
|Buffer/pH Control||Adjusts and controls the pH of the fluid||15%||sodium hydroxide|
|Solvent||Separates oil and water mixtures||15%||isoproponal|
|Surfactant||Reduces fluid surface tension and improves fluid recovery||13%||isotridecanol ethoxylate butoxy propanol methanol|
|Corrosion inhibitor||Protects well and tubing from corrosion.||5%||methanol isopropanol|
|Acid||Dissolves minerals and forms cracks in rock||2%||hydrochloric acid|
|Reduces friction of fluid in pipes to optimize rate and pressure||> 1%||ethylene glycol methanol glycerol|
Source: EWG, from DOGGR Well Stimulation Public Disclosure Report.
Comparison with EPA’s national data
In March 2015, the U.S. EPA released a report that analyzed data from the national FracFocus Chemical Disclosure Registry. The report was a preliminary step in the major EPA study that recently concluded that fracking had indeed contaminated some sources of drinking water across the country. It analyzed disclosures from 20 states for fracking jobs from early 2011 to February 2013 and identified a total of 692 distinct chemicals that had been used in oil and gas fracking operations (EPA 2015).
The EPA report shows that there are significant differences between the fracking chemicals used most often nationwide and those used most often in California. (See Table 2 for a complete comparison.) Among them:
- Methanol was the top chemical used nationally, reported in nearly three-fourths of oil fracking jobs but in only about 20 percent of California jobs. Methanol is listed as a Hazardous Air Pollutant under the federal Clean Air Act.
- Petroleum distillates (hydrotreated light) were the second most commonly reported chemical nationally and the sixth most reported in California.
- Crystalline silica was reported in only half of the national disclosures but in all of the California reports.
- Hydrochloric acid was reported in nearly 58 percent of national disclosures but in only 5 percent of California reports. Hydrochloric acid is also a federally listed Hazardous Air Pollutant.
- Heavy aromatic naphtha, a neurotoxin known to cause cancer in lab animals, was reported in nearly 22 percent of national reports but in less than 1 percent of California disclosures.
- Naphthalene, a known carcinogen, was 10 EWG.org California’s Fracking Fluids: The Chemical Recipe reported in almost 18 percent of disclosures nationally, compared to about 2 percent of those in California.
- Glutaraldehyde was the most common biocide nationally, reported in about a third of fracking jobs. It was not reported at all in California, where CMIT and MIT were the most commonly reported biocides.
- 2-BE, a glycol ether surfactant found in tap water in Pennsylvania, was reported in about one-fifth of the national disclosures but fewer than 5 percent of the California reports.
On average, fewer chemical additives were reported per fracking job nationally than in California. The median7 number of added chemicals per fracking job was 19 in California and 14 nationwide for both oil and gas jobs. EWG’s analysis of the California disclosure data showed that the most common number of chemicals per fracking job was 28.
Table 2. The top 40 fracking chemicals used in California, Dec. 2013-Feb. 2015, compared to national data from U.S. EPA’s March 2015 report, “Analysis of Hydraulic Fracturing Fluid Data from the FracFocus Chemical Disclosure Registry 1.0.”
|Rank||Chemical Abstract Service Number (CAS #)||Chemical Reported||Percent of California frack jobs reporting chemical||Percent of frack jobs reporting chemical in EPA national analysis (all oil wells)|
|1||14808-60-7||crystalline silica, quartz||100%||49.4%|
|2||91053-39-3||diatomaceous earth, calcined||100%||15.3%|
|4||7727-54-0||ammonium persulfate (per- oxydisulfuric acid, diammonium salt)||94.9%||59.6%|
|5||64742-55-8||petroleum distillate, hydrotreated light paraffinic (blend 2)||89.6%||7.9%|
|6||64742-47-8||petroleum distillates, hydrotreated light (blend 1)||89.6%||60.8%|
|7||14464-46-1||crystalline silica, cristobalite||88.0%||5.0%|
|17||1303-96-4||sodium tetraborate decahydrate||81.2%||10.7%|
|18||9025-56-3||hemicellulase enzyme concentrate||77.9%||6.5%|
|19||6419-19-8||nitrilotris (methylene phosphonic acid)||68.6%||3.6%|
|21||5131-66-8||propylene glycol butyl ether (1-butoxy-2-propanol)||64.3%||4.0%|
|22||138879-94-4||oxyalkylated amine quat (1,2-eth- anediaminium, n, n’-bis[2-[bis(2- hydroxyethyl)methylammonio] ethyl]-n,n’bis(2-hydroxyethyl)-n,n’- dimethyl-,tetrachloride)||63.5%||3.2%|
|27||14807-96-6||magnesium silicate hydrate (talc)||11.9%||3.3%|
|29||25038-72-6||vinylidene chloride/methylacrylate copolymer||11.9%||2.8%|
|31||9003-35-4||phenol formaldehyde polymer (phenolic resin)||11.3%||17.9%|
|35||7631-86-9||silica, amorphous - fumed||9.7%||NR|
|39||31726-34-8||polyethylene glycol monohexyl ether||9.0%||3.2%|
|40||104-76-7||2-ethyl hexanol (2-ethylhexan-1-ol)||8.8%||4.6%|
Source: Environmental Working Group, from DOGGR 2015 and EPA 2015.
NR = Not Reported.
7 The value that half the records were above and half below.
Contamination of drinking water: mechanisms are clear, but data are lacking
There are several ways that fracking fluids can potentially contaminate drinking water, and a number of cases of actual contamination have been reported (Hildenbrand et al 2015, Llewellyn et al 2015, EPA 2015b). However, the impact of hydraulic fracturing on water resources nationally is impossible to quantify because of the lack of data. Few studies exist, and the recent EPA report said it could not conclude “the frequency of impacts with any certainty” because it lacked access to water quality data or the needed data did not exist. What little data are available point to the following sources of possible contamination:
- Surface spills. Again, data are lacking. Existing estimates of the number of spills of hydraulic fracturing fluids nationally range from 100-to- 3,700 a year (EPA 2015b). The EPA found that most chemical spills resulted from equipment failures or leaks from storage containers (EPA 2015b). An extensive groundwater study in the Barnett Shale region in Texas found a pattern suggesting that some of the identified contaminants likely came from surface spills (Hildenbrand et al 2015).
- Well casing failures. There are estimates that well casings fail in up to 12 percent of new wells within the first year of operation (Ingraffea et al 2014). These failures may result in underground contamination of aquifers well outside of the immediate production zone.
- Migration of fluids. A report by the U.S. Geologic Service last year concluded that “new pathways can be created when injection pressures are applied during well stimulation,” allowing fracking fluids to migrate underground over significant distances (USGS 2014).
- Improper handling of wastes. In California, an ongoing investigation of thousands of improperly approved injection wells for oil and gas wastewater is producing troubling findings. On May 15, 2015, the oil and gas division submitted new information to the EPA identifying 53 injection wells that could potentially contaminate drinking and irrigation water, and an additional 207 wells that might affect potential drinking water sources (Bishop and Bohlen 2015). In May 2015, the Sierra Club and the Center for Biological Diversity sued the oil and gas division to stop the illegal wastewater injections.
As a result of lack of regulation and official negligence, the oil and gas industry has been able to claim that fracking fluid and recovered wastewater do not threaten and have never polluted drinking water, but that claim is no longer credible. We now know incontrovertibly that chemicals from fracking fluid and wastewater have contaminated drinking water in locations across the country.
To date, however, state and federal officials have been incapable or unwilling under existing regulations to place protection of public health ahead of the wishes of the oil and gas industry. Although California now probably has the nation’s most stringent regulations for fracking and the most comprehensive disclosure requirements of the chemicals used, those measures have not been enough to ensure that sources of drinking and agricultural water are safe from contamination. Stronger actions are needed.
- California should take steps to further regulate the dangerous chemicals used in fracking. An assessment of whether less harmful alternatives can replace the chemicals now in use is urgently needed.
- All citizens, and especially those living near fracking operations, have a right to understand the risks. Chemical safety data sheets should be submitted and posted along with the chemical disclosures on the website of the Division of Oil, Gas and Geothermal Resources and made available to residents adjacent to fracking operations. Nationally, chemicals used in fracking should be disclosed in a transparent program similar to California’s SB 4 program.
- There is a severe lack of data on the effects of hydraulic fracturing on drinking water resources in California and nationally. The state should support the recommendations for groundwater monitoring in areas of oil and gas well stimulation and properly enforce the model criteria for the regional groundwater- monitoring program developed under SB 4. This program should serve as a model for a national program to collect groundwater- monitoring data.
- The state must immediately stop the illegal injection of wastewater into potential sources of drinking or agricultural water.
- Integration of renewable energy sources is sorely needed. California must make clean energy a priority for the long term instead of relying on fossil fuels and dangerous practices using harmful chemicals.
Appendix 1: The 197 unique fracking chemicals publicly disclosed from 691 wells in California from 2014 to February 2015, ranked by the number of times they were reported. [Click here to download PDF, see page: 17]