due to increasing numbers 
 of home fires in which furniture was 
 often an item first ignited , the california bureau of electronic and 
 appliance repair , home furnishings and thermal insulation implemented 
 a residential flammability standard known as technical bulletin 117 
 ( tb-117 ) in 1972 . this standard required 
 that resilient filling materials used in upholstered furniture meet 
 a 12 s , open - flame test designed to reduce the ignition time and combustibility 
 of the material . to meet this standard , furniture manufacturers have 
 historically used additive chemical treatments , which primarily include 
 applications of brominated and/or organophosphate flame retardants 
 ( frs ) to the polyurethane foam used as filling materials . brominated frs work by releasing bromine radicals into the gas phase , 
 which help to quench the reactions that propagate fire . in contrast , 
 organophosphate frs typically work in the solid phase by increasing 
 a char layer , which reduces oxygen and diminishes the spread of the 
 flame . the high use of these types of frs 
 in furniture has been suggested 
 to contribute to higher exposure among the general population , particularly 
 for children , and to increased risks for adverse health outcomes . in 2001 , noren and meiryonte published a paper in which they examined 
 the historical trends in persistent organic pollutant levels in breast 
 milk collected from women in sweden as a means of evaluating temporal 
 changes in exposure . although they observed 
 decreases in dichlorodiphenyl trichloroethane ( ddt ) , dioxins , and 
 polychlorinated biphenyls with time ( due to bans and restrictions 
 placed on ddt use ) , the levels of polybrominated diphenyl ethers ( pbdes ) several successive studies 
 also observed similar trends for pbdes in human and animal tissues , suggesting that exposure was increasing with doubling times ranging 
 from 2 to 7 years . within the last 10 years alone , hundreds of studies 
 have been conducted examining the environmental distribution , fate 
 and toxicity of pbdes . due to mounting evidence suggesting that pbdes 
 were persistent , highly bioaccumulative , and potentially toxic , the 
 three primary pbde commercial mixtures ( pentabde , octabde and decabde ) 
 were subsequently either banned from use or voluntarily phased - out 
 of manufacturing , depending on the region . this led to a significant shift away from the use of pbdes ( i.e. , 
 pentabde ) and toward other types of brominated and organophosphate 
 frs to meet tb-117 . based on our previous studies , our 
 data suggest that manufacturers primarily moved to chlorinated organophosphate 
 flame retardants ( e.g. , tris(1,3-dichloro - isopropyl)phosphate , tdcipp ) , 
 or a mixture known as firemaster550 [ fm550 ] , which consists of a mixture 
 of brominated aryl esters and triaryl phosphate esters . new studies are now demonstrating that exposure 
 to tdcipp and fm550 is also becoming ubiquitous among the general 
 us population . the other chlorinated organophosphate frs ( e.g. , tris ( chloropropyl ) 
 phosphate , tcipp ) are now also detected ubiquitously in australian 
 and european populations as well . human exposure to additive 
 frs may occur through inhalation , ingestion , and dermal absorption . given that recent research indicates considerable potential for 
 dermal absorption of the chlorinated frs commonly found in furniture 
 ( tdcipp , tcipp ) , concern for human exposure 
 from contact with furniture and other foam - containing consumer products 
 is warranted . recent animal studies suggest that exposure to tdcipp 
 and components present in fm550 can lead to reproductive and developmental 
 effects including reduced fecundity , problems with heart development , 
 reductions in bone development and even cancer . therefore , the use 
 of current frs in residential furniture may still lead to increased 
 risks for adverse health outcomes . due to these concerns , and 
 to the fact that a majority of home 
 fires involving furniture are ignited via cigarettes and not via an 
 open flame , the state of california recently revised tb-117 ( now known 
 as tb117 - 2013 ) from an open flame test to a smolder - ignition standard . 
 in 2014 , the state of california added a new law ( sb1019 ) requiring 
 all furniture be sold with a label indicating whether or not the furniture 
 is chemically treated with a fr . however , it is currently unclear 
 how these changes to california standards will affect the use of frs 
 in furniture , and how these changes will relate to exposures among 
 the general population . to prioritize frs for human exposure 
 assessments and biomonitoring 
 programs , scientists and policy - makers must understand which frs are 
 used most frequently , and in what products . currently , this information 
 is not publicly available , and chemical treatments can be identified 
 only through material analysis . in 2011 and 2012 , we reported on the 
 levels of additive frs in infant products and residential sofas ; however , other types of products containing polyurethane foam were 
 not tested ( e.g. , mattress pads , chairs , pillows etc . ) . furthermore , 
 tb-117 was significantly altered in 2013 , which may alter the way 
 frs are used in furniture . therefore , to understand better the use 
 of and potential exposure to frs in products containing polyurethane 
 foam ( puf ) , we initiated a program in collaboration with duke university s 
 superfund research center that allowed members of the general us population 
 to submit samples for testing free of charge . to our knowledge , this 
 is the first and only free service available to the public for testing 
 frs in foam . our research objectives were to analyze products containing 
 puf for 7 common additive frs to determine which frs are more commonly 
 used across various products . a secondary objective was to determine 
 if the use of additive frs has changed over time . when submitting 
 samples for testing , participants were asked to provide information 
 on the type of product ( e.g. , sofa , chair , mattress , etc . ) , year and 
 state in which the product was purchased , and whether or not the product 
 contains a tb-117 label . between february 2014 and june 2016 here we summarize our findings from these 
 analyses , and report on trends by product category and changes in 
 flame retardant use over time . participant 
 enrollment and sample submission is handled through the project web 
 site ( http://foam.pratt.duke.edu ) . email advertisements 
 were used to assist recruitment , which was bolstered by news and media 
 reports on flame retardant chemicals , blogs mentioning our project 
 ( 31% of traffic to our web site ) , social media ( 5% 
 web site traffic ) , academic partners and relevant interest groups . participants were united states residents age 18 or older . 
 for each sample , participants completed a questionnaire regarding 
 contact information and product details including the product type , 
 whether the product was intended for a child or adult , what kind of 
 flammability standard label was present ( e.g. , ca tb-117 or cfr 1632 ) , 
 and year and state in which the product was purchased . product types 
 included sofas and loveseats ( i.e. , two - seat furniture pieces ) , chairs , 
 rocking chairs and recliners , other furniture , mattresses , mattress 
 pads ( i.e. , cushions that sit on top of and are separate from mattresses ) , 
 child mattresses , child car seats , pillows , other child products , 
 pit cubes / gymnastics equipment , other ( miscellaneous ) . following completion 
 of the questionnaire , participants were given instructions for sampling , 
 packaging , and mailing the puf sample to duke university for testing . each participant was asked to cut out a small marble - sized piece of 
 puf from their product , wrap it tightly in aluminum foil , seal it 
 in a plastic bag , and mail it to the address provided . approximately 
 6 to 8 weeks later , the participants were mailed a letter providing 
 their results . standards of the pentabde technical mixture , 
 2,2-bis(chloromethyl)propane-1,3-diyl - tetrakis(2-chloroethyl)bis(phosphate ) 
 ( v6 ) , 2-ethylhexyl 2,3,4,5-tetrabromobenzoate ( tbb , aka ehtbb ) and 
 ( 2-ethylhexyl ) tetrabromophthalate ( tbph , aka behtbp ) were purchased 
 from wellington laboratories . susan klosterhaus who had previously received the mixture from 
 great lakes chemical ( west lafayette , in ) . h. stapleton was provided 
 a sample of polyurethane foam from a foam manufacturer in north carolina 
 that used firemaster 600 ( fm600 ) in the foam , from which a sample 
 of fm600 was extracted and used as a standard in this project . triphenyl 
 phosphate ( tphp ) was purchased from sigma - aldrich ( st . louis , mo ) . tris(2-chloroethyl)phosphate ( tcep ) , tris(1-chloro-2-propyl ) phosphate 
 ( tcipp ) and tris(1,3-dichloroisopropyl)phosphate ( tdcipp ) were purchased 
 from sigma - aldrich ( st . louis , mi ) , pfaltz & bauer ( waterbury , 
 ct ) , and fluka ( st . louis , mo ) , respectively . dichloromethane ( dcm ) , 
 acetonitrile ( acn ) , water and methanol were purchased from honeywell 
 ( muskegon , mi ) preparation of 
 foam samples was 
 adapted from stapleton et al . , 
 5 ml of dcm was added to 50 mg of foam sample in a glass test tube , 
 and the solution was sonicated for 10 min . a 100 l aliquot 
 of the extract was diluted to 1 ml for analysis by gas chromatography 
 mass spectrometry ( gc / ms ) . a laboratory blank ( test tube containing 
 dcm but no foam ) was included with each batch of samples processed . foam extracts were first screened using gas chromatography mass spectrometry 
 ( gc / ms ) . based on gc analyses , some samples required further analysis 
 by liquid chromatography tandem mass spectrometry ( uplc / ms / ms ) . for 
 these samples , 100 l of extract was exchanged to 200 l 
 of methanol and diluted to 1 ml with water . due to the generally small 
 sample size , we were not able to conduct thorough testing to characterize 
 physical properties of the foam ( e.g. , density ) or classify the type 
 of polyurethane foam . a suite 
 of mass spectrometric 
 analyses were used to identify individual flame retardant ( fr ) chemicals 
 and evaluate commercial mixtures . frs in extracts were analyzed by 
 gc / ms in scan mode with both electron ionization ( agilent 7890 gc , 
 agilent 5795c ms , wilmington , de ) and electron capture negative ionization 
 ( agilent 6890 gc , agilent 5975n ms ) . separation was conducted on a 
 db-5 column ( agilent ) using a thermal gradient ( 40 c for 1 min , 
 18 c / min to 250 c , 1.5 c / min to 260 c , 25 
 c / min to 300 c , 300 c for 20 min ) . initial inlet 
 temperature was 80 c for 0.3 min and then ramped 600 c / min 
 to 275 c . to assist in detecting frs that were likely intentionally applied 
 to the foam to meet flame retardant standards , frs were semiquantitatively 
 analyzed using authentic standards ( listed above ) representing a fr 
 concentration equivalent to 1% by weight of foam . this concentration 
 was selected based on the amounts of frs typically applied to foam 
 to meet flame retardant standards to limit and avoid false positives . frs were rarely detected 
 in blanks , and whenever detected were well below a concentration equivalent 
 to 0.1% by weight of foam . uplc / ms / ms analysis for v6 was conducted 
 on an accela uplc system ( thermofisher scientific , bremen , germany ) 
 with thermofisher tsq vantage triple quadrupole mass spectrometer . uplc separation was conducted on hypersil gold , c18 column ( thermofisher , 
 100  2.1 mm , 1.9 m particle size ) using an acn : water 
 gradient ( 20% acn for 2 min to 99% acn at 13 min , held at 99% acn 
 for 2 min ) . injection volume was 20 l , and flow rate was 300 
 l / min . m / z to 360.8 m / z was used for quantification , 
 and transitions 582.9 m / z to 296.8 m / z and 582.9 m / z to 98.9 m / z were used 
 for confirmation . in total , seven fr commercial mixtures were evaluated 
 in this screen using authentic standards : fm550 ( tphp , isopropylated 
 tphp isomers , tbb and tbph ) , fm600 , tdcipp , tcipp , v6 , pentabde ( containing 
 tphp , isopropylated tphp isomers , and bde congeners 47 , 85 , 99 , 100 , 
 153 and 154 ) ,  tbpp  ( containing tphp and monodi- and 
 tributylated tphp ) . between 
 january 2014 
 and june 2016 , 1141 foam samples were received for testing and which 
 were collected from a wide variety of products including upholstered 
 furniture , mattresses , mattress toppers , a suite of child products 
 and others ( table 1 ) . foam samples were submitted from 567 different households and 
 products varied substantially by year of purchase ( 1960 to 2016 ) and 
 state of purchase . participant households represent 44 states , with 
 most participants living in the following states : california ( 24% ) , 
 north carolina ( 16% ) , massachusetts ( 9% ) , new york ( 6% ) , washington 
 ( 5% ) and new jersey ( 5% ) . similarly , samples were purchased from the 
 following states : california ( 22% ) , north carolina ( 10% ) , new york 
 ( 7% ) , massachusetts ( 5% ) , online purchase ( 5% ) , michigan ( 4% ) and 
 pennsylvania ( 3% ) . products were grouped into 12 categories , of which 
 the most abundant category was sofas and loveseats ( n = 451 , 40% , table 1 ; figure 1 ) . child 
 products ( e.g. , child car seats , child mattresses , sleep positioners ) 
 comprised 16% of all samples . some product categories ( e.g. , pillows ) 
 contained very few samples ; therefore , this paper reports primarily 
 on the 7 major nonmiscellaneous product categories : sofas and loveseats , 
 chairs , rocking chairs and recliners , mattress pads , child car seats , 
 child mattresses , and other child products . results from testing other 
 product categories are provided in the supporting information ( figure s1 ) . values in parenthesis are percentages 
 of products purchased in california under each column header . identification 
 of a flame retardant in puf samples was based on comparison to authentic 
 standards and to a fr mass spectral response greater than 1% by weight 
 of the foam . for all samples analyzed , 598 ( 52% ) were positively identified 
 as containing a fr based on our screening process and criteria ( table 1 , figure 1 ) . among the major product 
 categories , the portion of samples containing a fr ranged from 29% 
 ( n = 106 ) of mattress pads to 74% of child car seats 
 ( n = 98 ) . among sofas and loveseats , 45% contained 
 no identifiable fr , which is much higher than reported by stapleton 
 et al . , ( 2012 ) for couches purchased between 1985 and 2010 , for which 
 only 12% contained no known frs . the differences may be attributable 
 to the fact that the current study included many products purchased 
 2013 and later , for which time period we observed a decrease in fr 
 detection as described below . of all samples tested , 90 ( 8% ) contained 
 more than one fr , which is similar to results reported in our earlier 
 studies . there was no clear trend relating multiple 
 fr applications to product type ; however , the most commonly observed 
 combination of frs across all categories was tdcipp with tcipp . the 
 presence of more than on fr may be coapplication , or possibly cross - contamination 
 during manufacturing . across all samples analyzed tris(1,3,-dichloro-2-propyl)phosphate 
 ( tdcipp ) was the most frequently detected fr ( 24% of all samples tested ) , 
 followed by fm550 ( 10% ) > tris(2-chloroisopropyl)phosphate ( tcipp ) 
 ( 9% ) > pentabde ( 6.0% ) . this trend varied somewhat among the major 
 product categories ; however , tdcipp was still the most frequently 
 detected fr in all categories . tdcipp was also observed as the most 
 frequently detected fr in us sofas purchased between 1985 and 2010 , 
 followed by fm550 and a mixture of isobutylated triaryl phosphates 
 that we refer to as although no frs were detected in 48% of samples , this may not necessarily 
 indicate that these samples are not treated with flame retardants ; 
 the screening process is not likely to catch reactive or polymeric 
 frs that are bound to the foam structure or more strongly sorbed , 
 and our method may overlook frs for which the chemical composition 
 is unknown . no general trend was observed based on whether or 
 not products 
 were purchased in the state of ca , even for products that fall under 
 the regulatory guidance of tb-117 . for example , 28% of the sofas and 
 loveseats tested contained a fr and were purchased in ca ; however , 
 15% of the sofas and loveseats from ca that were tested did not contain 
 a fr ( table 1 ) . interestingly , 
 however , a greater percentage of child car seats ( 54% ) and child mattresses 
 ( 22% ) with no fr detected were purchased in ca than observed for fr - containing 
 products in the 7 major categories . this observation may partly reflect 
 changes to fr use in response to the 2011 addition of tdcipp to prop 
 65 , given that tdcipp is the most frequently detected fr for these 
 products , and that 84% of child car seats and 64% of child mattresses 
 were purchased after 2011 . trends on fr use based on state of purchase 
 must be considered with some caution given that ca was the most represented 
 state in the study with regard to where participants lived and where 
 products were purchased . to understand better 
 potential changes in fr use over time and across products , temporal 
 trends were examined among the product categories with the highest 
 sample submissions : sofas and loveseats ; chairs , rocking chairs and 
 recliners ; mattress pads ; and child car seats ( figure 2 ) . given that tb-117 is a california standard , 
 we also included the percent of samples purchased in the state of 
 california within each category . of the 828 samples analyzed in these 
 product categories , 97 had an unknown or uncertain year of purchase , 
 and were thus excluded from this analysis . in all product categories , 
 we observed an increase in the frequency of fr use up until 2014 . 
 for these product categories , 35% of samples purchased between 1950 
 and 1999 ( n = 124 ) , 61% of samples purchased between 
 2000 and 2004 ( n = 85 ) , and 68% of samples purchased 
 between 2005 and 2013 ( n = 390 ) contained a fr . however , 
 only 37% of the samples purchased between 2014 and 2016 ( n = 132 ) contained frs , representing a significant decrease in detection 
 frequency ( p < 0.001 , one - tailed fisher s 
 exact test ) from that observed in products purchased between 2005 
 and 2013 . this may suggest fr use has decreased recently , or it may 
 suggest that other types of frs are being used that we can not detect . 
 our results also indicate that the percentage of sofas and loveseats 
 purchased in the state of california does not relate to fr use across 
 years , and ranged from 26% ( 20142016 ) to 39% ( 20002004 ) . for chairs , rocking chairs and recliners , fr use similarly increased 
 among samples purchased between 2000 and 2004 ( 62% of samples , n = 13 ) when compared to samples purchased before 1999 ( 36% , n = 39 ) , and continued to increase in products purchased 
 through 2013 . as observed with sofas and loveseats , fr detection frequency 
 in chairs , rocking chairs and recliners decreased significantly ( p = 0.018 ) after 2013 . the detection of frs in mattress 
 pads was much lower overall than 
 use among the other three product categories . of the four samples 
 purchased between 1950 and 1999 , none contained a flame retardant . however , 2 of the 11 mattress pads ( 18% ) purchased between 2000 and 
 2004 , and 32% of the samples purchased between 2005 and 2013 ( n = 71 ) , and 29% of the samples purchased between 2014 and 
 2016 ( n = 15 ) did contain a flame retardant . no statistically significant trends in fr use were observed over time 
 for mattress pads . all samples of child car seats submitted 
 for testing were purchased 
 after 2008 , likely reflecting the short lifetime of child car seats . of those purchased between 2009 and 2013 , 91% contained frs ( n = 53 ) . however , fr detection frequency ( 50% , n = 42 ) decreased significantly ( p < 0.0001 ) in 
 car seats purchased after 2013 . these results may indicate a decline 
 in use of frs in child car seats , or that the industry is switching 
 to a new fr technology . given the voluntary 
 phase - out of pentabde in the us that occurred starting in 2005 , we 
 anticipated that a significant shift in the types of frs detected 
 would be observed based on the year in which the participants reported 
 purchasing these products . in figure 3 , the percentage of puf samples from sofas and loveseats 
 containing various frs is presented based on whether the product was 
 purchased before or after 2005 . of 156 sofas and loveseats reportedly 
 purchased before 2005 , 75 ( 48% ) contained a fr , with pentabde detected 
 most frequently ( 48% of all samples containing a fr ) , followed by 
 tdcipp ( 44% ) > fm550 ( 5% ) > tbpp ( 4% ) . most samples ( < 2005 ) 
 that 
 contained pentabde were from furniture ( i.e. , sofa , loveseat , chair , 
 rocking chair , recliner ) ; however , pentabde was observed in two mattresses , 
 two pillows and one stroller . pentabde was observed in 8 samples purchased 
 after the 2005 phase - out : three sofas , one chair , two mattresses , 
 one mattress pad , and a carpet pad . in contrast , no tcipp was observed 
 in sofas and loveseats purchased prior to 2005 , whereas tcipp - containing 
 samples comprised 13% of the samples purchased after 2005 ( of the 
 samples testing positive for a fr ) . across all products , the detection 
 frequencies of tdcipp , fm550 , tcipp and tbpp increased in samples 
 containing a fr purchased after 2005 , suggesting that all of these 
 frs may serve as pentabde replacements . a recent survey of 102 us 
 sofas likewise observed reduced pentabde detection in products purchased 
 between 2005 and 2010 . authors reported 
 the largest increase in the use of tdcipp , followed by fm550 . presence of 
 tdcipp , tbpp , pentabde , tcipp and fm550 in sofas and 
 loveseats containing a fr purchased before and after 2005 . note that 
 the sum of products containing a fr purchased after 2005 exceeds 100% 
 because some products ( 18 ) contained more than one fr . in addition to changes in fr use before and after 
 2005 , we also 
 examined differences before and after 2014 to examine potential shifts 
 in the chemical industry reflecting changes to the tb-117 flammability 
 standard and/or the 2011 addition of tdcipp to california s 
 proposition 65 list . in 2013 , the state of california amended tb-117 
 to require a smolder test instead of an open flame test for compliance 
 purposes , for which enforcement began in 2014 . within sofas and loveseats , 
 which fall under tb-117 - 2013 , frs were detected in 60% of samples 
 purchased before 2014 , which was considerably higher than the detection 
 frequency ( 29% ) observed in samples post 2014 ( figure 4 ) . among the samples containing a fr , tdcipp 
 was detected in 47% of sofas and loveseats purchased before 2014 , 
 which was in contrast to a detection frequency of only 11% in those 
 purchased after 2014 . conversely , the portion of products containing 
 tbpp and tcipp increased in more recent years . however , the percentage 
 of samples containing fm550 appeared not to vary , suggesting that 
 the use of fm550 was not altered significantly by the change in tb-117 . although our results may suggest that recent changes to tb-117 - 2013 
 may have an impact on the use of frs overall in these types of products , 
 purchase dates may not reflect manufacturing dates , which may be obfuscating 
 some of our results . given that this shift in regulation is fairly 
 recent , the number of samples manufactured after 2014 is also relatively 
 small in our sample population . evaluation of more samples made after 
 2014 is needed to shed further light on these trends . in addition , 
 tdcipp was added to california s proposition 65 list in 2014 , 
 which also may have affected the use of this chemical as a fr in puf . presence 
 of tdcipp , tbpp , tcipp and fm550 in ( a ) sofas and loveseats 
 and ( b ) child car seats purchased before and after 2014 . note that 
 the sum of child car seats containing an fr purchased after 2014 exceeds 
 100% because some products ( 8) contained more than one fr . for child car seats , overall fr detection frequency 
 decreased from 
 91% of samples purchased before 2014 to 50% of samples post 2014 . trends in detection of specific frs differed from those observed for 
 sofas and loveseats , which may reflect the fact that child car seats 
 do not fall under tb-117 - 2013 , but are federally regulated under fmvss 
 302 . tdcipp detection in child car seats decreased noticeably from 
 77% to 48% in car seats purchased before and after 2014 ( figure 4 ) . concomitantly , 
 tcipp detection increased from 29% to 52% , suggesting that tcipp may 
 be a replacement for tdcipp . given the health concerns for several of these frs , more attention 
 to the use and application of these chemicals in common household 
 goods is needed to evaluate health risks . studies have found significant 
 associations between levels of frs in house dust with body burden 
 levels , and common household products are postulated 
 to be a source of the frs to the dust . data generated from this fr screening project demonstrate that significant 
 changes have occurred in fr applications over the past few decades , 
 and potentially in the use of these chemicals overall . given that 
 this project is a public service - derived survey , there are likely 
 some biases and limitations . for example , participants may not report 
 product information ( e.g. , purchase state , year , label information ) 
 accurately . likewise , all demographic groups may not participate equally , 
 potentially leading to sampling bias , or nonrepresentation of the 
 entire country . despite these limitations , the database garnered from 
 this clearly , pentabde 
 is not used any longer as a fr in these products ; however , due to 
 their persistent properties , and the anticipated long lifetime of 
 some pieces of furniture ( e.g. , sofas ) , emissions of pbdes from furniture 
 and human exposure may be a concern for decades to come . furthermore , 
 our data also suggest that tdcipp use is decreasing , but like pentabde , 
 exposure may occur for decades . in addition , some products that were 
 not expected to contain frs ( e.g. , pillows ) , or products that have 
 not been thoroughly tested ( e.g. , mattress pads ) may also be sources 
 of exposure to people and the home environment . pillows in particular 
 may be a significant source of exposure given the proximity and duration 
 of time that people spend in contact with these products on a daily 
 basis . and last , given the change in the ca flammability standard 
 over the past few years , fr applications overall appear to be decreasing 
 in puf ; however , it is unclear whether use may increase in upholstery 
 and textiles , which may warrant testing of these materials as well .
flame retardant ( fr ) 
 chemicals have often been added to polyurethane 
 foam to meet required state and federal flammability standards . however , 
 some frs ( e.g. , pbdes and tdcipp ) are associated with health hazards 
 and are now restricted from use in some regions . 
 in addition , california s 
 residential furniture flammability standard ( tb-117 ) has undergone 
 significant amendments over the past few years , and tdcipp has been 
 added to california s proposition 65 list . 
 these events have 
 likely led to shifts in the types of frs used , and the products to 
 which they are applied . to provide more information on the use of 
 frs in products containing polyurethane foam ( puf ) , we established 
 a screening service for the general public 
 . participants residing 
 in the us were allowed to submit up to 5 samples from their household 
 for analysis , free of charge , and supplied information on the product 
 category , labeling , and year and state of purchase . between february 
 2014 and june 2016 , we received 1141 puf samples for analysis from 
 various products including sofas , chairs , mattresses , car seats and 
 pillows . 
 of these samples tested , 52% contained a fr at levels greater 
 than 1% by weight . 
 tris(1,3-dichloroisopropyl)phosphate ( tdcipp ) was 
 the most common fr detected in puf samples , and was the most common 
 fr detected in all product categories . 
 analysis of the data by purchasing 
 date suggests that the use of tdcipp decreased in recent years , paralleled 
 with an increase in the use of tcipp and a nonhalogenated aryl phosphate 
 mixture we call  tbpp .  in addition , we observed significant 
 decreases in fr applications in furniture products and child car seats , 
 suggesting the use of additive frs in puf may be declining , perhaps 
 as a reflection of recent changes to tb-117 and proposition 65 . 
 more 
 studies are needed to determine how these changes in fr use relate 
 to changes in exposure among the general population .