Unifix Math Counting Blocks Teaching Aid from Portland Public Schools: 1330 ppm Cadmium [a known carcinogen.]

A school teacher with Portland Public Schools (in Oregon) anonymously gave me these small plastic snap-together UNIFIX math / teaching aid blocks to test.  She initially had a concern that they might contain something toxic and unsafe for children primarily because of how they smell.

Here’s an Amazon link to see this product in the wild (not necessarily to use to purchase these, given they have Cadmium!): Link.

The presence of heavy metals generally would not impact the smell of an item, but I agreed to test them anyway as I hadn’t tested them yet and with all of the toxicants I have found in plastics recently this seemed like something definitely worth testing!. The teacher felt these would be especially important to test for heavy metals given they are ubiquitous in elementary schools. She wanted to make sure they were safe for her students and for all students.

When tested with an XRF instrument two of the colors (red and orange) had Cadmium levels that are at a concerning level (levels that would be considered illegal in Denmark – for example.) Below are the full XRF test results for each color cube (when tested for a full minute each). Metals not detected in “Consumer Goods Mode” are not listed:

1. Orange Plastic Block:
   • Cadmium (Cd): 578 +/- 15 ppm
   • Barium (Ba): 208 +/- 85 ppm
   • Selenium (Se): 133 +/- 6 ppm
   • Zinc (Zn): 42 +/- 7 ppm
   • Copper (Cu): 20 +/- 12 ppm
   • Nickel (Ni): 13 +/- 7 ppm
   • Iron (Fe): 49 +/- 17 ppm
   • Titanium (Ti): 3,944 +/- 294 ppm
2. Red Plastic Block:
   • Cadmium (Cd): 1,330 +/- 25 ppm
   • Arsenic (As): 7 +/- 4 ppm
   • Barium (Ba): 218 +/- 91 ppm
   • Selenium (Se): 289 +/- 8 ppm
   • Nickel (Ni): 16 +/- 8 ppm
   • Iron (Fe): 49 +/- 17 ppm
   • Titanium (Ti): 497 +/- 214 ppm
3. Mauve [Dark Red] Plastic Block:
   • Barium (Ba): 148 +/- 76 ppm
   • Antimony (Sb): 29 +/- 18 ppm
   • Zinc (Zn): 13 +/- 6 ppm
   • Copper (Cu): 22 +/- 12 ppm
   • Nickel (Ni): 12 +/- 7 ppm
   • Iron (Fe): 4,103 +/- 78 ppm
   • Titanium (Ti): 974 +/- 189 ppm
4. White Plastic Block:
   • Barium (Ba): 201 +/- 79 ppm
   • Iron (Fe): 35 +/- 18 ppm
   • Titanium (Ti): 8,425 +/- 360 ppm
5. Green Plastic Block:
   • Copper (Cu): 76 +/- 13 ppm
   • Nickel (Ni): 13 +/- 7 ppm
   • Iron (Fe): 33 +/- 16 ppm
   • Titanium (Ti): 3,451 +/- 285 ppm
6. Blue Plastic Block:
   • Barium (Ba): 178 +/- 89 ppm
   • Nickel (Ni): 12 +/- 7 ppm
   • Iron (Fe): 72 +/- 18 ppm
7. Black Plastic Block:
   • Barium (Ba): 181 +/- 86 ppm
   • Nickel (Ni): 13 +/- 7 ppm
   • Iron (Fe): 90 +/- 18 ppm

#SimpleSolution: While it is unknown whether or not the Cadmium would leach if put in to a child’s mouth, it seems a reasonable thing to be concerned about – especially since these are the perfect size for a child to pop one in their mouth to chew on. If you must use this product in your classroom or with your children, a simple solution would be to use the blocks without the orange and red ones (removing the orange and red ones and disposing of them.) As these are a consumer good they can go in the landfill even though they contain toxicants. You can read more about that here.

Alternately perhaps there is a European company (adhering to stricter standards?) that might make a similar but less toxic product? Please comment on this post if you know of an alternate brand of product with a similar application – a brand that might have higher standards from a toxicant perspective.

As always, please let me know if you have any questions.

Thank you for reading and for sharing my posts.

Tamara Rubin
#LeadSafeMama 

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