This blog post, originally shared in the Pharos Signal, includes information about parts of Pharos that are no longer available. Please use it for historical reference and for the other useful information it contains.

When purchasing ceramic wall or flooring tiles, focus on products made in the USA.  Not only will you help staunch the exodus of the ceramic tile industry to other continents, you will probably avoid bringing toxic heavy metals into your building project.

That is the main conclusion from our research into the ceramic tile industry, which culminated in this week’s opening of our newest category of product evaluations.  The Pharos building product database provides in-depth and product-specific analysis of the vast majority of floorings, including carpet, solid wood, engineered wood, rubber (natural and synthetic), vinyl, cork, polyolefin, and now ceramic tile flooring.

Transparency in the tile industry is on the increase, but full disclosure of material contents remains rare. The lack of specifics about some key ingredients – especially tile glazes and processing additives  -- required us, as with every category we have researched since 2009 -- to draw informed conclusions from patents, government studies, and upstream suppliers of raw materials.  We also benefited from open dialogue with industry leaders, including the Tile Council of North America, and Crossville Tile, the first company to disclose its tile ingredients though Pharos.

The results are found in Pharos' category description,  individual product profiles, and records that identify common ingredients of the ceramic tile body, glazes (leaded and unleaded), frits (leaded and unleaded, and a prototypical photocatalytic antimicrobial coating.  (Note: Only the category description is available without a subscription to Pharos. Click here to start your free trial and view our in-depth evaluations.)

Dirty Industry Migration

The Pharos research team came to realize that the ceramic tile industry has undergone two fundamental, and perhaps related, changes over the past two decades.

One: Production has shifted offshore. Imports now hold nearly 80 percent share of U.S. sales.  Beginning in the late 1990s, as with much of the U.S. manufacturing sector, free trade agreements led to the shuttering of factories. Low-cost power, labor, and land fueled the explosive growth of ceramic tile manufacturing and exports from China. Tile made in China now dominates the shelves of U.S. retailers.

Two: The factories that remain in the United States have nearly eliminated the use of toxic heavy metals in ceramic glazes, but overseas suppliers have not.

Historically, highly toxic heavy metals compounds, especially lead oxide used in glazes, were prevalent in ceramic tile production.  Several shuttered ceramic tile factories in the U.S. are now Superfund sites for cleanup of widespread heavy metal contamination.

Surviving tile producers in the U.S. say they have stopped using most heavy metals.  This claim is supported by our examination of EPA Toxics Release Inventory data for domestic ceramic floor and wall tile factories. This analysis reveals an historic decline in heavy metal releases over the past decade.

Lead compound releases dropped from over a ton to less than a pound.  Zinc, barium, chromium, manganese, cobalt, and nickel compound releases all declined by over 90 percent. Overall, heavy metal releases from US ceramic floor and tile producers dropped by 93.6% between 2002 and 2012, as shown below.

Data synthesized from industry reports to the Toxics Release Inventory, US Environmental Protection Agency.
(a) Antimony compounds (which are developmental and reproductive toxicants) are used as colorants in some ceramic tiles, including lead-free tiles made in the USA.

These gains, however, are offset by the migration of manufacturing to countries where transparency of material content is scarce, and where the use of toxic heavy metal compounds in tile glazes continues to be widespread. A 2010 Spanish study, for instance, examined three ceramic glazes and found that two contained lead oxide, and one contained cadmium oxide.  Also in 2010, the Ecology Center tested 39 ceramic tiles for sale at Home Depot and Lowes.  The tests found that 74 percent of the tiles “contained detectable lead, with levels as high as 1,900 parts per million.”

The use of heavy metal compounds in ceramic tile introduces substantial hazards for tile plant workers, surrounding communities, and watersheds.  Heavy metal glazing processes harm the industry’s most vulnerable workers.

In La Victoria, Ecuador, for example, many families make ceramic tiles and pottery at small worksites next to their homes.  Many of these tiles are shipped to the United States.  La Victoria is considered a lead-exposure “hotspot” because the villagers, including children, glaze the ceramics with lead from car batteries.  Harvard Medical School doctors tested lead in the blood of village children, and found an average of 510 micrograms per liter (µg/L), and a maximum of 1000 µg/L.  The U.S. Centers for Disease Control and Prevention considers 50 µg/L to be a “blood level of concern,” and recommends chelation treatment for children with blood levels of 450 µg/L or higher.

Health and environmental impacts from manufacturing are also found at the largest scales of production. Foshan, in Guangdong Province, is the hub of China’s ceramic tile industry. This region produces one-quarter of the world’s floor and wall tile.  The industry is blamed for chronic “severe particle pollution” and acid rain in the greater Pearl River Basin.

China now accounts for about half of the world’s ceramic tile production, but this status is peaking.  While production continues to increase, natural resources are stressed and labor costs are increasing. Tile Today, an Australian industry publication, reports, “many Chinese companies are themselves re-locating to countries such as Vietnam and Cambodia in search of cheaper labor.”

In today’s globalized market, the dirtiest industries swiftly migrate to the planet's lowest cost places.

Other Exposures

Heavy metal releases can also occur in the cutting of ceramic tile during construction and during demolition and disposal.  Less understood are potential exposures during use, especially when tiles are cleaned or abraded over time.

We have not identified any studies that examine potential exposures to heavy metals abraded from ceramic tile glaze during consumer use.  Nor have we seen any studies addressing potential migration of heavy metals from tile when they are exposed to cleaning agents.

Some tiles also have nanoscale ingredients in surface coatings, applied in a secondary firing process, after glazing.  These particles are ultra-fine, less than 200 nanometers in diameter.  Nano-scale ingredients include silver, copper, and titanium dioxide.  Health impacts of inhaling nanoscale particles is poorly understood, but a growing body of evidence points to increased biological activity from exposure that could potentially harm pulmonary systems.

These potential exposure pathways to harmful content should be a priority for further research.

Recommendations

Absent full disclosure of materials contents, consumers should assume that any glazed tile not made in the United States contains heavy metals in the surface layer.  In high traffic areas, especially where children are present, in the absence of disclosure, the safest choices would be unglazed tile or a glazed tile that is rated high for traffic abrasion and stain resistance.

Tile abrasion ratings are grouped into six classifications.  These are called Groups, Classes, or P.E.I. (Porcelain Enamel Institute) ratings, scaled from zero (0) to five (5).  Group 0-rated tile is suitable for walls only, not floors.    Group 5 is for “ultra heavy traffic” areas. Look for tiles rated at least a “4” to ensure high resistance to scratches, stains, and degradation.

Ceramic tile can be a relatively low-impact material for a flooring or wall project. This can be accomplished with by specifying tiles that:

1. are made-in-USA;
2. have full public disclosure of material contents, including frits, glazes, and pigments;
3. carry an abrasion rating of at least four (especially if glazed or coated with undisclosed content); and,
4. do not have coatings with antimicrobials and/or nanoscale particles.

These simple steps can ensure that the ceramic tile you choose will not expose workers, building occupants, and the global environment to toxic materials.

Follow HBN Senior Researcher Jim Vallette on Twitter: @HBNJim

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