About HealthyToys.org
Methodology
Detailed Methodology and Methodological Limitations
The
general methodology used to test the toys and children's products found
on the HealthyToys.org site is detailed below.
Researchers selected toys and other children's products that represented a cross section of some of the most popular items used by U.S. children. The products were purchased at chain stores including Target, Kmart, Toys R Us, Babies R Us, TJ Maxx, and Wal-Mart, as well as drug stores, dollar stores, on-line retailers and independent toy stores. Purchase locations included Ann Arbor and Ypsilanti, Michigan; Oakland, California; and Albany, New York. The sampling was not random or designed to be representative of all toys on the market.
Researchers strove to select toys from a variety of "toy categories" as established by the toy industry. These categories are: action figures & collectibles, activity gyms & play mats, arts & crafts supplies, backpacks, bath toys, crib toys, feeding products, bibs, dolls, costumes, infant books, soft & plush toys, pacifiers, rattles & teethers, outdoor toys & sporting goods, preschool & interactive toys, shoes, trains & construction toys, and vending machine toys.
XRF Testing Methodology
Researchers tested products using a handheld X-ray fluorescence (XRF) device manufactured by Innov-X Systems (download XRF Factsheet). The XRF analyzer uses a technology known as x-ray fluorescence spectrometry to detect chemical elements, such as lead, cadmium, chlorine, arsenic, mercury, tin, and antimony.
The elemental composition of the materials reveals the presence of potentially hazardous chemicals, such as heavy metals, and also allows researchers to infer the possible presence of toxic chemicals or materials, including brominated flame retardants (BFRs), polyvinyl chloride (PVC) and possibly phthalate plasticizers. We have translated the research results into a HealthyToys.org toy rating system to allow users to easily compare the chemical levels of a variety of popular toys and children's products. There are a number of chemicals of concern that cannot be detected by this technology.
As several different organizations contributed data to this project, researchers conducted tests in several locations across the country. The exact XRF device sampling protocol is described below.
XRF Calibration – XRF machines (manufactured by
Innov-X Systems) were calibrated at the beginning of each round of sampling
using the stainless steel clip, as well as the EC681 standard. Both calibrations
were done once with a test length of 60 seconds. Results were compared
to the known levels in the sample. During testing, a standardization was
taken after every 200 readings, using both the stainless steel clip and
the EC681 standard. In addition, one time standardization was performed
with Wako Chemical USA ABS discs with cadmium, chromium, lead in high & low concentrations
(NMIJ CRM 8106-a & NMIJ CRM 8105-a) and PVC disk standards (low
and high concentrations).
Testing - Standard testing time was 30 seconds. The
XRF machine was preset to test for the full 30 seconds. Only one test
was taken per component/material of a product. An attempt was made to
sample major components/materials of each toy. The actual number of samples
per product varied. Because the X-ray penetrates from just a few microns
(metal) to 1/4 inch (plastics and other softer substrates), the measurement
should be considered a surface measurement or near surface measurement.
Background sampling - Prior to the start of testing,
the background was sampled with the XRF. The same background was used
for all samples, whenever possible. When backgrounds were used, they were free of all chemicals of concern.
Machine positioning - When sampling, the XRF machine
was held in a position perpendicular to the product being tested, without
compressing the material. Tests were conducted on the flattest part of
the product, and the entire analyzer window was covered by the material
being tested, when possible. Products were not dismantled to test interiors.
Levels of Detection – LODs for highlighted elements
are as follows:
| Element | Manufacturers Detection Limits(1) |
Observed Detection Limits (30 second sample)(2) |
| Antimony | 50-150 ppm | 109 ppm |
| Arsenic | 10-100 ppm | 1 ppm |
| Bromine | 10-100 ppm | 2 ppm |
| Chlorine | 1% - 5% | 2.80% |
| Chromium | 10-100 ppm | 39 ppm |
| Cobalt | 10-100 ppm | 37 ppm |
| Copper | 10-100 ppm | 38 ppm |
| Lead | 10-100 ppm | 5 ppm |
| Mercury | 10-100 ppm | 7 ppm |
| Nickel | 10-100 ppm | 27 ppm |
| Tin | 50-150 ppm | 130 ppm |
(1) InnovX Model ABC XRF Detector detection estimates
based on 1-2 minute test times and detection confidence of 3-sigma, or
99.7% confidence. Detection limits are a function of testing time, sample matrix and presence of interfering
elements.
(2) Observed detection limits varied by type of material
being tested. Detection limits presented here are the lowest observed
from all testing.
Quality Assurance/Product Variation - In order to evaluate the variation per product to assess and verify the accuracy of our testing, some repeat samples were taken. This process took place once every 200 samples, and was done for at least one product in every product category. Repeat samples are taken in three different ways:
- three readings taken from the same sampling location of one product
- three readings taken from three different sampling locations (consisting of the same material, color, etc.) on the same product
- three readings taken from the same sampling location on three different but identical products
All repeat sample data was recorded and submitted for review, but is
NOT included in the product database.
Data Interpretation - We interpreted the results using
the concentrations and deviations reported by the analyzer, together with
visual examination of the spectra generated by the instrument. The analyzer
reports concentrations of elements by analyzing the spectra using reference
data for the elements it reports, and measuring the area under the curve
in the spectrum. We visually examined the spectra to confirm the presence
of elements with known interferences (lead, bromine, and arsenic), and have not reported
them where we could not confirm presence.
Methodological Limitations
The levels of lead, cadmium, chlorine, and other elements shown in this website are those reported by the XRF analyzer manufactured by Innov-X Systems, Inc. Our testing methodology uses standards with known levels of certain elements to check the accuracy of the analyzer in one type of matrix material. However, the toys and other products we tested are made of many different types of materials, in some cases even within the same product. These materials may interfere with the analyzer's ability to quantify the elements accurately. In addition, where the materials in a single product are not homogeneous, the test results may vary depending on the orientation between the object under test and the testing device. Where the testing is not able to isolate a single material, the reported levels may represent an averaging of the levels in the different materials. Interferences can occur between elements as well, such as with lead and arsenic, resulting in poorer precision. To the extent possible, we attempted to establish the degree of the interference.
Therefore, the levels we report provide a general indication of the levels in the products in order to guide consumers on product choices. More exhaustive testing with the XRF, as well as laboratory testing, could provide more detailed findings on the levels of elements and associated compounds.
