![Blue Shallow Heath Potteries Bowl (Sausalito, California): 125,000 ppm Lead [For context 90 ppm Lead is considered unsafe in children's items.]](https://tamararubin.com/wp-content/uploads/2019/06/Heath-Ceramics-Blue-Glazed-Stoneware-Bowl-Lead-Safe-Mama-5.jpg)
When tested with an XRF instrument this blue glazed ceramic bowl by Heath Potteries of Sausalito, California (year of manufacture is unknown) had the following readings:
Food Surface / Blue Glazed Interior of Bowl
- Lead (Pb): 838 +/- 28 ppm
- Barium (Ba): 585 +/- 38 ppm
- Antimony (Sb): 25 +/- 12 ppm
- Tin (Sn): 284 +/- 14 ppm
- Zinc (Zn): 876 +/- 44 ppm
- Copper (Cu): 8,210 +/- 187 ppm
- Iron (Fe): 3,780 +/- 187 ppm
- Bismuth (Bi): 36 +/- 10 ppm
- Vanadium (V): 106 +/- 23 ppm
- Titanium (Ti): 918 +/- 56 ppm
- Indium (In): 28 +/- 8 ppm
- Cobalt (Co): 5,923 +/- 200 ppm
Brown Glazed Under Side of Bowl
- Lead (Pb): 125,000 +/- 4,500 ppm
- Barium (Ba): 6,152 +/- 433 ppm
- Tin (Sn): 10,200 +/- 600 ppm
- Zinc (Zn): 16,900 +/- 700 ppm
- Copper (Cu): 306 +/- 68 ppm
- Iron (Fe): 8,277 +/- 498 ppm
- Vanadium (V): 2,504 +/- 179 ppm
- Titanium (Ti): 14,500 +/- 800 ppm
- Zirconium (Zr): 13,600 +/- 700 ppm
- Manganese (Mn): 1,479 +/- 328 ppm
At first glance it appears that the base (underside) of this bowl is unglazed, however upon closer examination the underside is glazed with a brown glaze that is slightly lighter in shade than (but very similar to) the brown color of the substrate of the clay.
Each area was tested for a minimum of 120 seconds (two full minutes) using an XRF instrument testing in “Consumer Goods” mode. All test results reported on this blog are science-based and replicable. Metals not listed in the reading sets above were not detected by the XRF in “Consumer Goods” mode. All tests are also done on a freshly calibrated instrument.
For context (so you have a better understanding of what the above numbers may indicate): newly manufactured items intended for use by children are considered unsafe (and illegal) if the glaze, paint or coating is greater than 90 ppm Lead (as detectable with an XRF.) Dishware (modern and vintage) is not regulated in the same way (or with the same strict standards) as toys and other items intended for use by children.
To see more dishes I have tested, click here.
As always, thank you for reading and for sharing my posts.
Please let me know if you have any questions.
![Blue Shallow Heath Potteries Bowl (Sausalito, California): 125,000 ppm Lead [For context 90 ppm Lead is considered unsafe in children's items.]](https://tamararubin.com/wp-content/uploads/2019/06/Heath-Ceramics-Blue-Glazed-Stoneware-Bowl-Lead-Safe-Mama-4.jpg)
![Blue Shallow Heath Potteries Bowl (Sausalito, California): 125,000 ppm Lead [For context 90 ppm Lead is considered unsafe in children's items.]](https://tamararubin.com/wp-content/uploads/2019/06/Heath-Ceramics-Blue-Glazed-Stoneware-Bowl-Lead-Safe-Mama-3.jpg)
![Blue Shallow Heath Potteries Bowl (Sausalito, California): 125,000 ppm Lead [For context 90 ppm Lead is considered unsafe in children's items.]](https://tamararubin.com/wp-content/uploads/2019/06/Heath-Ceramics-Blue-Glazed-Stoneware-Bowl-Lead-Safe-Mama-2.jpg)
![Blue Shallow Heath Potteries Bowl (Sausalito, California): 125,000 ppm Lead [For context 90 ppm Lead is considered unsafe in children's items.]](https://tamararubin.com/wp-content/uploads/2019/06/Heath-Ceramics-Blue-Glazed-Stoneware-Bowl-Lead-Safe-Mama-1.jpg)
Thank you! This was part of our wedding dinnerware, bought new in 1993. So sad/mad that we have used these all these years without knowing the danger. Now to get rid of them.
Hi Cheryll, Heath has not been very responsive about their historic product – since they have new ownership… but it might be worth sharing the link with them and asking them to swap out the older product (officially vintage as it is more than 20 years old) for new similar Lead-free product. [Their new product is generally Lead-safe or Lead-free.] I don’t know how they will respond. I know they are aware of my testing. I have spoken with the new owner in the past 5 years… so it might at least be worth a call!
Tamara
They declined
🙁
I do appreciate you doing this testing, but I should note, it doesn’t seem like 125,000 ppm can possibly be an accurate measurement. 125,000 parts per million would mean that the dish is 12.5% lead. Lead weighs 11.342 grams per cubic centimeter — so if you are able to calculate the volume of the plate (I suggest submerging in water say in a big pyrex and then seeing how much volume it displaces) you can calculate the plate’s density. You could probably use algebra to estimate to if the measurement was accurate then:
[mass of plate] = [12.5% of volume * density of lead] + [87.5% of volume * density of 1.362 gram per cubic centimeter for fired clay]
How close this is to the mass of the plate will reveal how accurate or inaccurate the measurement of lead content is.
The fact that fired clay is about 1/10th the density of lead means that it would likely be very, very heavy if true that it was 12.5% lead.
Hi Mike,
It’s Leaded glaze – it’s in the glaze at those levels, not the substrate. The XRF reads surface levels (for metals) of the item tested. With some variation depending on the substrate material and the density of the surface coating – the instrument usually does not read past findings of high amounts of Lead – especially at this high level. So it is not reading the Lead level of the substrate. The substrates on these dishes are often below 100 ppm Lead.
Thank you for commenting.
Tamara
Hi Tamara,
So happy to have found your website!
Might you know how many years ago Heath Ceramics started making lead-free products? We purchased a lot of their dish ware about two years ago. Thank very much.
It was about 8 or 10 years ago when they switched ownership!
T