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PFOA is a pervasive pollutant in human blood, as are other PFCs

PFCs: Global Contaminants: PFOA is a pervasive pollutant in human blood, as are other PFCs

April 3, 2003

April 2003

DuPont, 3M and other PFC manufacturers had ample indications decades ago that PFOA and other perfluorochemicals contaminate the blood of the general U.S. population. How and why they ignored the warning signs is one of the more distrubing chapters in the unfolding tragedy of PFC pollution.

In studies the 3M Company submitted to the government in 2001, scientists reported finding PFOA in the blood of 96 percent of 598 children tested in 23 states and the District of Columbia. [Extract | Full Document] Although this remains the largest study of children's blood, it was not the first. In 1981 DuPont found PFOA in umbilical cord blood from one baby and blood from a second baby born to female workers at its Teflon plant in Parkersburg, West Virginia. Among seven pregnant workers monitored by DuPont, two gave birth to babies with birth defects - one an "unconfirmed" eye and tear duct defect, and one a nostril and eye defect [Full Document]. That same year, DuPont reassigned 50 women from the plant [1].

Between 1972 and 1989, no less than nine studies were published on levels of PFCs in blood from the general population. PFOA was first tentatively identified in human blood as early as 1976, about the time PCBs were banned. In studies conducted in the past six years, industry scientists have detected PFOA in the vast majority of samples tested from nearly 3000 people in the US, including blood samples from 598 children, 238 elderly Washington State residents, and approximately 2000 blood bank donors.

Scientists have now found 15 PFCs in human blood - every PFC for which they have tested. In industry's 2001 study of six PFCs in human blood, scientists found four at higher levels in children than in adults. And children showing the highest levels were within the range of what has been measured in 3M workers [3][Extract | Full Document]. Recent laboratory studies heighten concerns about the effects these chemicals might have on children's health and development [4]. PFOA was found at similar levels in children and adults, but children may be at higher risk to the incremental effects of PFOA exposures simply because their bodies carry higher levels of other PFCs with toxicities similar to that of PFOA.

Once introduced, PFOA circulates in the body for years. If new exposures to PFOA could somehow be stopped, the body would require an estimated 4.4 years to excrete half the mass of PFOA accumulated in organs and tissues [2]. But since humans appear to be exposed frequently, perhaps daily, through consumer products and environmental contamination, the fact that the body can slowly excrete PFOA has less relevance to human health than the fact that PFOA appears to be continually reintroduced.

Even if PFOA were banned from use, its concentration could continue to build in the environment and in human blood. Over time other fluorinated compounds in common consumer products will degrade to their terminal breakdown product - PFOA. The rate at which this transformation will occur is not known, but could require decades or centuries, given what is known about degradation rates of other precursor PFCs. Humans could be exposed to ever-increasing amounts of PFOA through exposure routes driven by environmental contamination (tap water, food, and air, for example), even as post-ban exposures to PFOA from consumer products decline.

Fifteen PFCs have been found in human blood. In nearly 20 studies conducted between 1972 and 2002, scientists have found all 15 PFCs targeted in lab analyses, including:


  • Eight chemicals in the PFOS family (the sulfonates), most stemming from the original Scotchgard formulation. Scientists have detected PFOS itself, and five chemicals that appear as intermediates in the breakdown chain from the active Scotchgard ingredients to the terminal breakdown product (PFOS), including M570, M566, PFOSAA, and PFOSA. They have detected THPFOS, a chemical structurally related to PFOS, and PFHS and THPFDS, cousins of PFOS with a 6- and 10-carbon chains, respectively, instead of an 8-carbon chain like PFOS. [24]. [Excerpt | Full Document]
  • Seven chemicals in the PFOA family (the carboxylic acids), most stemming from Teflon products, and telomer alcohol and acrylate polymer products like Stainmaster and Zonyl chemicals used in food packaging. Scientists have found PFOS itself, and chemical sisters to PFOA characterized by carbon chain lengths ranging from 6 to 12 (chemicals referred to as C6, C7, C9, C10, C11, and C12). [Excerpt | Full Document]

Evidence of blood contamination in the 1970s. Early work to define human contamination by 3M chemicals was done not by the company but by dentists researching fluoride in the human body. Dr. Donald Taves of the University of Rochester's School of Medicine and Dentistry reported a surprising finding in a workup of a sample of his own blood. His analyses showed that some of the fluoride in his blood appeared to be organic, and unrelated to the types of fluoride added (controversially) to public drinking water supplies for purposes of dental hygiene.

In 1976 Dr. Taves and his collaborators tentatively identified one of the organic fluorines in human blood samples as one of 3M's perfluorinated organics - PFOA, or perfluorooctanoic acid [5]. The authors speculated that multiple perfluorocarbons appeared be present in human blood, and that some might be branched, or sulfonated (another group of 3M's perfluorochemicals). The authors presciently speculated on the source of these chemicals in blood:

"These findings suggest that there is widespread contamination of human tissues with trace amounts of organic fluorocompounds derived from commercial products.... A series of compounds having a structure consistent with that found here for the predominant form of organic fluorine in human plasma is widely used commercially for their potent surfactant properties. For example, they are used as water and oil repellants in the treatment of fabrics and leather. Other uses include the production of waxed paper and the formulation of floor waxes...The prevalence of organic fluorine in human plasma is probably quite high since 104 of the 106 plasma samples tested here and all 35 in an earlier study... had measureable quantities.... Computer assisted literature searches using Medline, Toxline and Chemcon developed no information on [metabolism and toxicology of these chemicals]. This was surprising with respect to the widespread commercial use of such compounds." [5].

A total of nine studies were completed between 1972 and 1989 quantifying levels of organic fluorine in human blood - in the general population in the US, Argentina, China, and Japan [6 (p.13)]. In 1976 3M began testing for - and finding - PFOA in workers' blood [6 (p.13)], but for 31 years after Taves' initial discovery, industry apparently and perhaps willfully failed to pursue studies that almost surely would have defined and confirmed the extent to which PFOA had contaminated the general population.

Despite the many findings of PFCs in human blood available in the peer-reviewed literature, 3M's medical director expressed "surprise" [7] when 1997 company-sponsored tests showed PFOS not only in workers' blood, but also in supposedly clean blood - samples from U.S. blood banks that were to be used as control samples in the tests. 3M withheld the findings for nine months while conducting confirmatory tests.

3M began a series of studies at their environmental laboratory to define the extent to which their chemicals contaminate people and the environment. In March and April 1998 3M's environmental lab finalized ten new studies that confirmed the presence of PFCs in the blood of the general population.

Perfluorochemicals were found in 18 pooled blood bank samples from all across the U.S. and in blood samples taken in the remote Linxian and Shandong provinces in rural China in samples drawn in 1984 and 1994. In only one group of samples were PFCs not found: ten archived blood samples taken from Korean War-era U.S. military recruits sampled between 1948 and 1951, about 10 years before PFOS chemicals went into commercial production.

Perfluorochemicals are found in blood samples from these groups

PFC detected

Not detected in



1948-1951 - Korean War era U.S. military recruits, 10 pooled samples

1957 - Sweden, 10 individual samples



1969-1971 - Michigan, 5 individual samples from a breast cancer study



1971 - Sweden, 10 individual samples



1976 - U.S., 6 pooled samples from heart disease study



1980 - U.S., 3 pooled samples from heart disease study



1984 - Linxian, rural China province, 6 individual samples*



1985 - U.S., 3 individual samples from heart disease study



1994 - Shandong, rural China province, 6 individual samples*



1995 - U.S. children in 23 states plus District of Columbia



1999 - U.S. elderly in Seattle, Wash.



2000 to 2002 - U.S. blood from commercial and blood bank sources

PFOS, PFOA, PFOSA, PFOSAA, M570, M556, C6, C7, C9, C10, C11, C12, THPFOS, THPFDS


*Note: In 3M documents AR226-0178[8] and AR226-0202[9], the levels of PFOS found in the 1984 and 1994 rural China samples are not distinguished separately. Three of the 12 individual samples from the 2 sample groups were composited for a total of 9 samples analyzed. PFOS was found in 3 of these 9 samples at levels between 1 and 5 ppb.

Source: AR226-0178[8], AR226-0202[9], and AR226-0036[10].

PFCs in children's blood. On May 15, 2001, three years to the day from 3M's first "notice of substantial risk,"[11] alerting EPA to the widespread contamination of humans and wildlife with their Scotchgard chemical, PFOS, 3M's Medical Director Larry Zobel gave EPA more significant news - some perfluorochemicals appear to be far more prevalent in children than in adults, and in some children, levels are as high as in 3M plant workers [3].

3M had based all prior blood tests for the general population on pooled samples from blood supply warehouses. In a new series of tests, 3M analyzed individual samples from 598 children ages 2 through 12 from 23 states and the District of Columbia, and from 600 adults (primarily ages 20-69) from six blood banks across the U.S. 3M's May 15th 2001 report to EPA showed that of the six PFCs found in the blood samples, four are found at higher levels in children than in adults [EWG Extract | EWG Full Document]. And children showing the highest levels are within the range of what has been measured in 3M workers [3]. Recent laboratory studies [4, 12] heighten concerns about the effects these chemicals might have on children's health and development. 3M's May 15, 2001 report to EPA shows that:


  • All 598 children and 883 adults tested have organic fluorinated chemicals in their blood. For many individual perfluorochemicals, some people have levels below the level of quantification. However, every person sampled thus far has detectable levels of organic fluorine. This type of fluorine is unrelated to the fluoride that is added to public drinking water supplies and is considered to be a surrogate measure for the presence of perfluorochemicals [13, 14].
  • Children showing the highest levels are within the range measured in 3M plant workers. PFOS was found in the group of children tested at a maximum concentration of 515 ppb. In 3M's Sumitomo plant in Japan, the highest level measured in plant workers in a 1999 study was 628 ppb [15]. Notably, the U.S. Environmental Protection Agency found that workers' exposures to PFOS are dangerously close to the levels at which adverse effects are reported in studies of laboratory animals, in what EPA refers to as a potentially unacceptable "margin of exposure" [16]. 3M's new blood study for the first time puts some children in a range overlapping with worker exposures. The same is true for PFOA. At the 3M plant in Decatur, AL, worker blood levels of PFOA ranged from 40 to 12,700 ppb in 2000, while PFOA was detected in children as high as 56 ppb [17][Extract | Full Document].
  • Some children have levels of perfluorochemicals in their blood at far higher levels than initial tests had shown. A 1999 pilot study of 12 children showed a maximum concentration of PFOS in sera of 115 ppb; the new study puts the maximum at 515 ppb. In the 1999 study, PFHS was found at a maximum of 100 ppb. In 3M's 2001 study, PFHS was found at more than seven times this level (a maximum of 712 ppb). Children at the highest levels of exposure show concentrations up to 48 times those of an average child.
  • Levels are higher in children than in adults in the general population. Of the six PFCs found in the blood samples in 3Ms 2002 study, four are found at higher levels in children than in adults (PFHS, PFOSAA, M570, and M556)[EWG Extract | EWG Full Document]. Levels of PFHS are notably higher in children than in adults. In short-term laboratory animal studies, PFHS causes cellular damage to the thyroid and disrupts the ability of cells to communicate with each other, just like PFOS and PFOA or chemicals that break down into PFOA.
  • One of the perfluorochemicals, M556, is far more prevalent in children than adults. 3M found this chemical in every one of the 598 children tested, but in fewer than five percent of the adults tested. M556 is an intermediate breakdown product of Scotchgard chemicals used in fabric and carpet protection, as the body converts the chemicals into PFOS. This result points to the possibility that children are exposed to higher levels of Scotchgard compared to adults, perhaps because of different behavior patterns. Alternatively, children could metabolize these chemicals more slowly than adults, which would lead to children being exposed to perfluorinated metabolites for longer periods of time [22].

PFCs may be even longer-lived in the human body
than previously suspected.

The 2001 children's blood study came when 3M was also backtracking on claims of how long-lived these chemicals are in the human body. 3M's estimates of the half-life of PFOS in the human body (the time it takes humans to excrete half of the amount of the chemical in their bodies) have oscillated between about one and nine years. In a 2002 study based on serum levels of PFOS in nine former 3M plant employees, 3M scientists estimate that the chemical's half-life in people is 8.7 years [2] [Extract | Full Document].

In the same group of former employees, 3M has most recently estimated a human half-life of 4.4 years for PFOA [2]. The estimated human half-life has increased as 3M has tracked workers more thoroughly [2, 23] [Extract | Full Document].

One peculiarity of perfluorochemicals is that the half-life in the body is less relevant to health concerns than it is for other chemicals. Scientists have found no mechanism by which PFOA and other terminal PFCs can be broken down in the environment. This means that every PFOA molecule on the planet is here to stay. Opportunities for humans (and other animals) to be exposed continuously to PFOA would continue even if it were banned.



[1] Environmental Working Group (EWG). 2002. DuPont Hid Teflon Pollution For Decades. Available online at

[2] Burris, JM., Lundberg, JK., Olsen, G., Simpson, C and Mandel, J (2002). Determination of serum half-lives of several fluorochemicals: Interim Report #2. Study Sponsor: 3M Company, Corporate Occupational Medicine Department, US EPA AR226-1086.

[3] 3M. 2001. TSCA 8(e) supplemental notice for sulfonate-based and carboxycylic-based fluorochemicals -Docket numbers 8EHQ-1180-373; 8EHQ-1180-374; 8EHQ-0381-0394; 8EHQ-05980373. U.S. EPA Administrative Record AR226-1019.

[4] York, RG (2002). Oral (gavage) two-generation (one litter per generation) reproduction study of ammonium perfluorooctanoate (APFO) in rats. Report prepared for 3M, St. Paul, MN by Argus Research (Horsham, PA). Sponsor's Study No. T-6889.6., Reviewed in US EPA AR226-1092.

[5] Taves, DR., Guy, WS and Brey, WS. 1976. Organic fluorocompounds in human plasma: prevalance and characterization. In Biochemistry involving carbon-fluorine bonds. A symposium sponsored by the Division of Fluorine and Biological Chemistry at the 170th meeting of the American Chemical Society. Chicago, IL. August 26, 1975ed. Washington DC, American Chemical Society. Vol.: 117 - 134.

[6] 3M. 1999. Perfluorooctane Sulfonate: current summary of human sera, health and toxicological data. U.S. EPA Administrative Record AR226-0548.

[7] 3M. 2000. Charles Reich, Executive Vice President of Specialty Material Markets for 3M: "It was a complete surprise that it [PFOS] was in the blood bank supplies." The Washington Post, May 17, 2000.

[8] 3M. 2000. Laboratory composite report: analytical reports of data for fluorochemical analysis in human sera. U.S. EPA Administrative Record AR226-0178.

[9] 3M. 2000. Composite analytical laboratory report on the quantitative analysis of fluorochemicals in environmental samples: Report Number FACT GEN-021, GEN-024, GEN-030, GEN-033, LRN-W2491, W2845, W3197, EOO-1386. U.S. EPA Administrative Record AR226-0202.

[10] 3M. 1998. Working memorandum on data quality assessment [of the mean and range of PFOS (ppb) levels in current and historical human populations]. U.S. EPA Administrative Record AR226-0036.

[11] 3M. 1998. TSCA 8(e) supplemental notice: sulfonate-based and carboxycylic-based fluorochemicals -Docket numbers 8EHQ-1180-373; 8EHQ-1180-374; 8EHQ-0381-0394; 8EHQ-05980373. U.S. EPA Administrative Record AR226-0540.

[12] Christian, MS., Hoberman, AM and York, RG. 1999. Oral (gavage) fertility, developmental and perinatal/postnatal reproduction toxicity study of PFOS in rats. Conducted for 3M (St. Paul, MN) by Argus Research Laboratories, Inc. Protocal Number 418-008, Study Number T-6295.9 Reviewed in OECD 11-21-02 Hazard Assessment of Perfluorooctane Sulfonate (PFOS) and its Salts.

[13] Ubel, FA., Sorenson, SD and Roach, DE. 1980. Health status of plant workers exposed to fluorochemicals--a preliminary report. Am Ind Hyg Assoc J 41(8): 584-9.

[14] Gilliland, FD and Mandel, JS. 1996. Serum perfluorooctanoic acid and hepatic enzymes, lipoproteins, and cholesterol: a study of occupationally exposed men. Am J Ind Med 29(5): 560-8. Reviewed in US Environmental Protection Agency Administrative Record AR226-1137 (pages 153-155; PDF page 50-52).

[15] Burris, J., Olsen, GW., Mandel, JH and Schumpert, JC. 1999. Determination of serum flurochemical levels in Sumitomo 3M employees. Final Report. 3M Company, 3M Medical Department, Epidemiology, 220-3W-05, FYI-0500-01378. Reviewed in OECD Hazard Assessment for PFOS (Available online here).

[16] US EPA (US Environmental Protection Agency). 2000. Email message from Charles Auer (EPA) to OECD. U.S. EPA Administrative Record AR226-0629.

[17] Environmental Protection Agency (EPA). 2002. Revised draft hazard assessment of perfluorooctanoic acid and its salts, November 4, 2002. U.S. EPA Administrative Record AR226-1136.

[18] 3M. 2002. TSCA 8(e) substantial risk notice on: perfluorohexane sulfonate potassium salt (no CAS number). U.S. EPA Administrative Record AR226-1138.

[19] Hu, W., Jones, PD., Upham, BL., Trosko, JE., Lau, C and Giesy, JP. 2002. Inhibition of gap junctional intercellular communication by perfluorinated compounds in rat liver and dolphin kidney epithelial cell lines in vitro and Sprague-Dawley rats in vivo. Toxicol Sci 68(2): 429-36.

[20] DuPont. 2002. The updated copy of DuPont Product Stewardship on December 17, 2001. U.S. EPA Administrative Record AR226-1069.

[21] DuPont Haskell Laboratory. 2002. Results of an oral gavage combined 90-day repeated dose and one-generation reproductive toxicity study in rats for poly (oxy-1,2-ethanediyl) alpha-hydro-omega-hydroxy- ether, with alpha-fluoro- omega (2-hydroxyethyl) poly (difluoromethane) (1:1) (telomer B monoether)(CAS Number 65545-80-4; non-HPV). US Environmental Protection Agency: Toxic Substance Control Act (TSCA) Section 8(e) Submission Received from 10/15/01 thru 12/07/01: 8EHQ-1001-14915. November 5, 2001. Available online at

[22] Olsen, GW., Burris, JM., Lundberg, JK., Hansen, KJ., Mandel, JH and Zobel, LR (2002). Final Report: Identification of fluorochemicals in human sera. III. Pediatric participants in a group A streptococci clinical trial investigation, Study conducted by Corporate Occupational Medicine, Medical Department, 3M Company, 220-3W-05, St. Paul, MN.

[23] Burris, JM., Olsen, G., Simpson, C and Mandel, J (2000). Determination of serum half-lives of several fluorochemicals: Interim Report #1. Study Sponsor: 3M Company, Corporate Occupational Medicine Department, US EPA AR226-0611.

[24] 3M. 2002. Analysis of pooled human sera and plasma and monkey sera for fluorocarbons using exygen method ExM-023-071. Report prepared for 3M, St. Paul, MN by Exygen Research, State College, PA. Sponsor study number E02-1071; Exygen Study Number: 023-082 U.S. EPA Administrative Record AR226-1152.