Common Ingredients: Vitreous Glazes (unleaded)

Representative Manufacturers


Used in Product Categories: Tile Components, Sanitary Ware Components , Tiles, Sanitary Ware, Flooring, Ceramic Floor Tiles, Toilet Tanks, One Piece Toilets & Toilet Bowls, Toilet Seats

Content status: Sufficient Content Record

Description:

Vitreous glazes seal clay-based ceramic products and provide a shiny and smooth surface. This glass-like coating can be transparent, colored or opaque, and can prevent water from being absorbed into the clay beneath.

Vitreous glazes are mixtures of minerals, clays, and frits (which in turn are primarily metal oxides, blended and smelted).

"Base glaze formulations usually contain frits of different nature in varying proportions (30-60%), and other non-fritted constituents (usually crystalline aggregates) of very different natures and characteristics, in accordance with the targeted final glaze properties.  Some of these constituents such as feldspars, nephelines, and zinc oxide contribute together with the frits to forming the glassy matrix of the glze.  Others, however, like zirconium silicate and corundum hardly dissolve in the glassy phase. Their function is to enhance glaze abrasion resistance to a certain extent, besides acting as opacifying (zirconium (IV) silicate) or matting agents (aluminum oxide)."  (Esmalglass)

In 1997, EPA noted, “Basic carbonate white lead has been the preferred leaded glaze ceramic manufacture for hundreds of years… However, white lead and other lead oxides are more soluble than other forms of lead, and because the lead leaches out over time, they are being phased out by the industry. The ceramics industry is addressing this solubility problem by adding lead to glaze in frit form.” (EPA 1997 - lead.pdf ) Since then, the use of lead oxides in frits has also declined.

Some floor and wall tile manufacturers do not use lead oxide or other lead substances in glazes. 

This record for vitreous glazes evaluates mixtures that do not contain lead.

Glazes account for approximately 1-6% of the overall tile, depending upon the application (Industrieverband Keramishche EPD, Sectoral Life Cycle Analysis of Ceramic Tile, Comparative Life Cycle Anlaysis of Flooring Materials). Typically, wall tiles have greater glaze content than floor tiles, however that can vary by manufacturer. 

This percentage can be higher in sanitaryware.  One industry source estimates a toilet and tank combination can contain 6.5 lbs of glaze (American Standard patent).

Direct Content Hazards:

REPRODUCTIVE EU - Annex VI CMRs - Reproductive Toxicity - Category 1B - from Boric Oxide + 8
PERSISTENT EC - CEPA DSL - Persistent - from ALUMINUM OXIDE
CANCER MAK - Carcinogen Group 3B - Evidence of carcinogenic effects but not sufficient for classification - from KAOLIN CLAY + 5
RESPIRATORY AOEC - Asthmagens - Asthmagen (Rs) - sensitizer-induced - from ALUMINUM OXIDE + 1
EYE IRRITATION Japan - GHS - Serious eye damage / eye irritation - Category 2A - from Boric Oxide + 3
ORGAN TOXICANT Japan - GHS - Specific target organs/systemic toxicity following single exposure - Category 1 - from ZINC OXIDE + 7
ACUTE AQUATIC EU - GHS (H-Statements) - H400 - Very toxic to aquatic life - from ZINC OXIDE + 6
CHRON AQUATIC Malaysia - GHS - H410 - Very toxic to aquatic life with long lasting effects - from ZINC OXIDE + 6
MAMMALIAN US EPA - OPP - Registered Pesticides - FIFRA Registered Pesticide - from KAOLIN CLAY + 5
SKIN IRRITATION New Zealand - GHS - 6.3A - Irritating to the skin (Cat. 2) - from Boric Oxide
TERRESTRIAL New Zealand - GHS - 9.3C - Harmful to terrestrial vertebrates - from ZINC OXIDE
RESTRICTED LIST US EPA - DfE SCIL - Yellow Triangle - best available in class but some hazard profile issues - from Boric Oxide + 5
MULTIPLE Québec CSST - WHMIS 1988 - Class D2A - Very toxic material causing other toxic effects - from KAOLIN CLAY + 6
DEVELOPMENTAL MAK - Pregnancy Risk Group D - from ALUMINUM OXIDE + 1
GENE MUTATION EU - Manufacturer REACH hazard submissions - H341 - Suspected of causing genetic defects (unverified) - from Frits, chemicals (unleaded)
SKIN SENSITIZE EU - Manufacturer REACH hazard submissions - H317 - May cause an allergic skin reaction (unverified) - from Frits, chemicals (unleaded)
POSITIVE LIST German FEA - Substances Hazardous to Waters - Non-Hazardous to Water (Water Hazard Class 0 NWG) - from ALUMINUM OXIDE + 1

Potential Residual Hazards:

See Process Chemistry Research tab for details on residuals and other substances used in manufacture.

CANCER CA EPA - Prop 65 - Carcinogen - from ANTIMONY TRIOXIDE + 22
DEVELOPMENTAL CA EPA - Prop 65 - Developmental toxicity - from LITHIUM CARBONATE + 2
REPRODUCTIVE EU - Annex VI CMRs - Reproductive Toxicity - Category 1B - from Boric Oxide + 10
PERSISTENT EC - CEPA DSL - Persistent - from ALUMINUM OXIDE + 2
ENDOCRINE TEDX - Potential Endocrine Disruptors - Potential Endocrine Disruptor - from Titanium dioxide
GENE MUTATION Japan - GHS - Germ cell mutagenicity - Category 2 - from QUARTZ + 1
RESPIRATORY AOEC - Asthmagens - Asthmagen (Rs) - sensitizer-induced - from ALUMINUM OXIDE
EYE IRRITATION Australia - GHS - H318 - Causes serious eye damage - from CALCIUM OXIDE + 9
SKIN IRRITATION EU - GHS (H-Statements) - H314 - Causes severe skin burns and eye damage - from PHOSPHORUS PENTOXIDE + 11
SKIN SENSITIZE Japan - GHS - Skin sensitizer - Category 1 - from ZIRCONIUM DIOXIDE
ORGAN TOXICANT Japan - GHS - Specific target organs/systemic toxicity following single exposure - Category 1 - from BARIUM OXIDE, ANHYDROUS + 13
ACUTE AQUATIC EU - GHS (H-Statements) - H400 - Very toxic to aquatic life - from ZINC OXIDE + 10
CHRON AQUATIC Malaysia - GHS - H410 - Very toxic to aquatic life with long lasting effects - from ZINC OXIDE + 8
MAMMALIAN EU - GHS (H-Statements) - H302 - Harmful if swallowed - from BARIUM CARBONATE + 16
TERRESTRIAL New Zealand - GHS - 9.3B - Ecotoxic to terrestrial vertebrates - from LITHIUM CARBONATE + 1
FLAMMABLE Québec CSST - WHMIS 1988 - Class B4 - Flammable solids - from FERROUS OXIDE
REACTIVE Québec CSST - WHMIS 1988 - Class E - Corrosive materials - from CALCIUM OXIDE + 2
RESTRICTED LIST US EPA - DfE SCIL - Yellow Triangle - best available in class but some hazard profile issues - from Boric Oxide + 10
MULTIPLE Québec CSST - WHMIS 1988 - Class D2A - Very toxic material causing other toxic effects - from ANTIMONY TRIOXIDE + 7
BIOACCUMULATIVE US EPA - PPT Chemical Action Plans - Low bioaccumulation potential - TSCA Criteria met - from BARIUM CARBONATE
POSITIVE LIST German FEA - Substances Hazardous to Waters - Non-Hazardous to Water (Water Hazard Class 0 NWG) - from ALUMINUM OXIDE + 1

Common Contents:

Material % Wt. Part % Wt. Whole Hazard GreenScreen Renewable
Substance Residual Manufacturing
Frits, chemicals (unleaded) 30.00 - 62.00 % 30.00 - 62.00 %       LT-P1
[68476-25-5] FELDSPAR 20.00 - 30.00 % 20.00 - 30.00 %       LT-UNK
[37244-96-5] NEPHELINE SYENITE 10.00 - 30.00 % 10.00 - 30.00 %   LT-UNK
[1303-86-2] Boric Oxide 10.00 - 20.00 % 10.00 - 20.00 %     LT-1
[1332-58-7] KAOLIN CLAY 4.00 - 6.00 % 4.00 - 6.00 %       LT-UNK
[10101-52-7] Zirconium silicate 2.00 - 30.00 % 2.00 - 30.00 %     LT-UNK
[1344-28-1] ALUMINUM OXIDE 0.50 - 40.00 % 0.50 - 40.00 %     2
[1314-13-2] ZINC OXIDE 0.50 - 20.00 % 0.50 - 20.00 %     1

Process Chemistry - Known or Potential Residuals:

Material Hazard Type Frequency % Wt. Part % Wt. Whole Notes
Substance Residual Manufacturing
[1344-28-1] ALUMINUM OXIDE - from FELDSPAR     Component Integral (known) Unknown Unknown
[1344-28-1] ALUMINUM OXIDE - from KAOLIN CLAY     Reactant Integral (known) 37.40 - 39.60 % Unknown
[1344-28-1] ALUMINUM OXIDE - from Frits, chemicals (unleaded)     Component Frequent (known) Unknown Unknown
[1317-70-0] Anatase titanium dioxide - from KAOLIN CLAY   Component Integral Unknown Unknown
[1309-64-4] ANTIMONY TRIOXIDE - from Frits, chemicals (unleaded)     Component Frequent 0.12 - 0.88 % Unknown
[513-77-9] BARIUM CARBONATE - from Frits, chemicals (unleaded)     Component Frequent (known) Unknown Unknown
[1304-28-5] BARIUM OXIDE, ANHYDROUS - from FELDSPAR   Component Integral (known) Unknown Unknown
[1304-28-5] BARIUM OXIDE, ANHYDROUS - from Frits, chemicals (unleaded)   Component Frequent Unknown Unknown
[1303-86-2] Boric Oxide - from Frits, chemicals (unleaded)     Component Occasional/Rare (known) Unknown Unknown
[1305-78-8] CALCIUM OXIDE - from FELDSPAR     Component Integral (known) 0.70 - 1.40 % Unknown
[1305-78-8] CALCIUM OXIDE - from KAOLIN CLAY     Reactant Frequent (known) 0.00 - 0.20 % Unknown
[12136-45-7] dipotassium oxide - from FELDSPAR   Component Integral (known) 0.10 - 0.70 % Unknown
[12136-45-7] dipotassium oxide - from KAOLIN CLAY   Reactant Integral (known) 44.40 - 45.70 % Unknown
[12136-45-7] dipotassium oxide - from Frits, chemicals (unleaded)   Component Frequent (known) Unknown Unknown
[1345-25-1] FERROUS OXIDE - from FELDSPAR       Component Frequent (known) 0.10 % Unknown
[1309-37-1] FERRIC OXIDE     Pollutant/ Contaminant Frequent (known) Unknown Unknown
[1345-25-1] FERROUS OXIDE - from KAOLIN CLAY       Pollutant/ Contaminant Integral (known) 0.40 - 0.80 % Unknown
[1309-37-1] FERRIC OXIDE     Pollutant/ Contaminant Frequent (known) Unknown Unknown
[12057-24-8] Lithium oxide - from Frits, chemicals (unleaded)       Component Frequent (known) Unknown Unknown
[554-13-2] LITHIUM CARBONATE     Reactant Integral (known) Unknown Unknown
[1309-48-4] MAGNESIUM OXIDE - from FELDSPAR       Component Integral (known) Unknown Unknown
[1344-28-1] ALUMINUM OXIDE     Pollutant/ Contaminant Frequent (known) Unknown Unknown
[1305-78-8] CALCIUM OXIDE     Pollutant/ Contaminant Frequent (known) Unknown Unknown
[1309-37-1] FERRIC OXIDE     Pollutant/ Contaminant Frequent Unknown Unknown
[7631-86-9] SILICA, AMORPHOUS     Pollutant/ Contaminant Frequent (known) Unknown Unknown
[1309-48-4] MAGNESIUM OXIDE - from Frits, chemicals (unleaded)       Component Frequent (known) Unknown Unknown
[1344-28-1] ALUMINUM OXIDE     Pollutant/ Contaminant Frequent (known) Unknown Unknown
[1305-78-8] CALCIUM OXIDE     Pollutant/ Contaminant Frequent (known) Unknown Unknown
[1309-37-1] FERRIC OXIDE     Pollutant/ Contaminant Frequent Unknown Unknown
[7631-86-9] SILICA, AMORPHOUS     Pollutant/ Contaminant Frequent (known) Unknown Unknown
[1309-48-4] MAGNESIUM OXIDE - from KAOLIN CLAY       Reactant Frequent (known) 0.00 - 0.10 % Unknown
[1344-28-1] ALUMINUM OXIDE     Pollutant/ Contaminant Frequent (known) Unknown Unknown
[1305-78-8] CALCIUM OXIDE     Pollutant/ Contaminant Frequent (known) Unknown Unknown
[1309-37-1] FERRIC OXIDE     Pollutant/ Contaminant Frequent Unknown Unknown
[7631-86-9] SILICA, AMORPHOUS     Pollutant/ Contaminant Frequent (known) Unknown Unknown
[1314-56-3] PHOSPHORUS PENTOXIDE - from KAOLIN CLAY     Reactant Frequent (known) 0.00 - 0.30 % Unknown
[14808-60-7] QUARTZ - from KAOLIN CLAY   Component Integral (known) 1.00 % Unknown
[7631-86-9] SILICA, AMORPHOUS - from Frits, chemicals (unleaded)     Component Frequent (known) Unknown Unknown
[7631-86-9] SILICA, AMORPHOUS - from FELDSPAR     Component Integral (known) 60.70 - 68.30 % Unknown
[7631-86-9] SILICA, AMORPHOUS - from KAOLIN CLAY     Reactant Integral (known) 44.40 - 45.70 % Unknown
[11126-22-0] Silica, vitreous - from FELDSPAR   Component Integral (known) Unknown Unknown
[1313-59-3] SODIUM OXIDE - from Frits, chemicals (unleaded)     Component Frequent (known) Unknown Unknown
[1313-59-3] SODIUM OXIDE - from FELDSPAR     Component Integral (known) 3.00 - 9.80 % Unknown
[1314-11-0] Strontium oxide - from FELDSPAR   Component Integral (known) Unknown Unknown
[18282-10-5] Tin Oxide - from Frits, chemicals (unleaded)     Component Frequent (known) 0.20 % Unknown
[13463-67-7] Titanium dioxide - from KAOLIN CLAY     Pollutant/ Contaminant Integral (known) 0.40 - 1.70 % Unknown
[1314-13-2] ZINC OXIDE - from Frits, chemicals (unleaded)     Component Frequent (known) 0.50 - 30.00 % Unknown
[1314-23-4] ZIRCONIUM DIOXIDE - from Frits, chemicals (unleaded)   Component Frequent (known) Unknown Unknown

Process Chemistry - Other:

Material Hazard Type Frequency % Wt. Part % Wt. Whole Notes
Substance Residual Manufacturing
[21645-51-2] Alumina trihydrate - from ALUMINUM OXIDE     Reactant Frequent Unknown Unknown
[1318-16-7] BAUXITE - from ALUMINUM OXIDE     Reactant Integral Unknown Unknown
[10043-35-3] BORIC ACID - from Boric Oxide   Reactant Frequent Unknown Unknown
[1302-42-7] SODIUM ALUMINATE - from ALUMINUM OXIDE   Reactant Frequent Unknown Unknown
[1310-73-2] Sodium hydroxide - from ALUMINUM OXIDE     Reactant Frequent Unknown Unknown
[1313-59-3] SODIUM OXIDE - from KAOLIN CLAY     Reactant Integral 0.06 - 0.10 % Unknown
[1330-43-4] SODIUM TETRABORATE - from Boric Oxide   Reactant Frequent Unknown Unknown
[7664-93-9] SULFURIC ACID - from Boric Oxide     Reactant Frequent Unknown Unknown
[7440-66-6] ZINC - from ZINC OXIDE       Reactant Frequent Unknown Unknown
[1314-98-3] ZINC SULFIDE - from ZINC OXIDE   Reactant Occasional/Rare Unknown Unknown
[14940-68-2] Zircon (Zr(SiO4)) - from Zirconium silicate   Reactant Integral Unknown Unknown

GreenScreen for Safer Chemicals Full Assessment: None available

Highest concern GreenScreen score : Benchmark 1

Cradle to Cradle Certified™ List Hazards

What are C2C hazards and what do these colors mean?

How to Use These Scores in a C2C Assessment

Acute and Chronic Tox. Acute Aquatic Tox. Chronic Aquatic Tox.
C M R+D E O D I O/D/I N IrS+IrE SnS+SnR Fish Inv. Alg. Any Fish Inv. Alg. Any T P B Climate Organohalogen Toxic Metal Other Mult
R - R - - - ? R - Y R ? ? ? R - - - R ? R/Y - G NL NL - R

Full Hazard List By Endpoint:

Carcinogenicity US EPA - IRIS Carcinogens - (1999) Data are inadequate for an assessment of human carcinogenic potential: Red, Yellow, or Green
MAK - Carcinogen Group 3B - Evidence of carcinogenic effects but not sufficient for classification: Red
US EPA - IRIS Carcinogens - (1986) Group D - Not classifiable as to human carcinogenicity: Red, Yellow, or Green
US EPA - IRIS Carcinogens - (2005) Inadequate information to assess carcinogenic potential: Red, Yellow, or Green
Mutagenicity not listed
Reproductive Toxicity (Repro + Dev) MAK - Pregnancy Risk Group D: Red, Yellow, or Green
Australia - GHS - H360Fd - May damage fertility. Suspected of damaging the unborn child: Red
EU - REACH Annex XVII CMRs - Toxic to Reproduction Category 2 - Substances which should be regarded as if they impair fertility or cause Developmental Toxicity in humans: Red
Japan - GHS - Toxic to reproduction - Category 1B: Red
Korea - GHS - Reproductive toxicity - Category 1 [H360 - May damage fertility or the unborn child]: Red
EU - SVHC Authorisation List - Toxic to reproduction - Prioritized for listing: Not rated
Japan - GHS - Toxic to reproduction - Category 2: Red
Endocrine Disruption not listed
Oral Toxicity not listed
Dermal Toxicity not listed
Inhalative Toxicity New Zealand - GHS - 6.9A (inhalation) - Toxic to human target organs or systems (Cat. 1): Not rated
Oral, Dermal, and/or Inhalative Toxicity Japan - GHS - Specific target organs/systemic toxicity following repeated exposure - Category 1: Red
Japan - GHS - Specific target organs/systemic toxicity following single exposure - Category 3: Green
Japan - GHS - Specific target organs/systemic toxicity following single exposure - Category 1: Red
Neurotoxicity not listed
Skin, Eye, and Respiratory Corrosion/Irritation Japan - GHS - Serious eye damage / eye irritation - Category 2A: Yellow
New Zealand - GHS - 6.3A - Irritating to the skin (Cat. 2): Not rated
New Zealand - GHS - 6.4A - Irritating to the eye (Cat. 2A): Not rated
Skin and Respiratory Sensitization AOEC - Asthmagens - Asthmagen (Rs) - sensitizer-induced: Red
AOEC - Asthmagens - Suspected asthmagen (R) - but does not meet AOEC criteria): Not rated
Acute Aquatic Toxicity (Fish) New Zealand - GHS - 9.1A (fish) - Very ecotoxic in the aquatic environment: Not rated
Acute Aquatic Toxicity (Invertibrates) New Zealand - GHS - 9.1A (crustacean) - Very ecotoxic in the aquatic environment: Not rated
Acute Aquatic Toxicity (Algae) New Zealand - GHS - 9.1A (algal) - Very ecotoxic in the aquatic environment: Not rated
Acute Aquatic Toxicity (Fish, Invertibrates, and/or Algae) German FEA - Substances Hazardous to Waters - Non-Hazardous to Water (Water Hazard Class 0 NWG): Not rated
EU - GHS (H-Statements) - H400 - Very toxic to aquatic life: Red
Japan - GHS - Hazardous to the aquatic environment (acute) - Category 1: Red
Malaysia - GHS - H400 - Very toxic to aquatic life: Red
Chronic Aquatic Toxicity (Fish) not listed
Chronic Aquatic Toxicity (Invertibrates) not listed
Chronic Aquatic Toxicity (Algae) not listed
Chronic Aquatic Toxicity (Fish, Invertibrates, and/or Algae) Australia - GHS - H410 - Very toxic to aquatic life with long lasting effects: Red
EU - GHS (H-Statements) - H410 - Very toxic to aquatic life with long lasting effects: Red
Malaysia - GHS - H410 - Very toxic to aquatic life with long lasting effects: Red
Japan - GHS - Hazardous to the aquatic environment (chronic) - Category 1: Not rated
Terrestrial New Zealand - GHS - 9.3C - Harmful to terrestrial vertebrates: Not rated
Persistence EC - CEPA DSL - Persistent: Red or Yellow
Bioaccumulation not listed
Climatic Relevance not listed
Organohalogen not listed - This chemical is not on the Pharos list of organohalogens, but we may have missed a few. Please double-check the chemical structure to confirm there are no carbon-halogen bonds.
Toxic Metal not listed - This chemical is not on the Pharos list of toxic metals, but we may have missed a few. Please double-check the chemical structure to confirm there are no toxic metals.
Other (Human Health) not listed
Multiple Endpoints EC - CEPA DSL - Inherently Toxic in the Environment: Red
EC - CEPA DSL - Inherently Toxic to Humans (iT human): Red
ChemSec - SIN List - CMR - Carcinogen, Mutagen &/or Reproductive Toxicant: Red
EU - Annex VI CMRs - Reproductive Toxicity - Category 1B: Red
EU - GHS (H-Statements) - H360FD - May damage fertility. May damage the unborn child: Red
German FEA - Substances Hazardous to Waters - Class 1 - Low Hazard to Waters: Red
Québec CSST - WHMIS 1988 - Class D2B - Toxic material causing other toxic effects: Red
German FEA - Substances Hazardous to Waters - Class 2 - Hazard to Waters: Red
Québec CSST - WHMIS 1988 - Class D2A - Very toxic material causing other toxic effects: Red
  • Chen, Zheng, James Michael Mchale. "Antimicrobial glaze and porcelain enamel via double layer glaze with high zinc content." American Standard Int Inc, Applicant. Patent WO2006130308 A2. December 7, 2006.
  • Comparative Life Cycle Assessment of flooring materials: ceramic versus marble tiles (2001)
  • Economic Impact Analysis of the Clay Ceramics Manufacturing NESHAP: Final Rule (EPA 2003)
  • Esmalglass: "Obtaining Smooth, White Floor Tile Glazes from Zirconium-Free Frits" (Castellon - Spain - Qualicer 98)
  • Ferro Corp., "Ceramic tile and glaze for use thereon," US Patent No. US 6,174,608 B1 (2001)
  • Ferro Corp., "Tile Glaze," US Patent No. US 6,132,832 (2000)
  • Ferro Corp., "Transparent Tile Glaze," US Patent Application No. US 2005/0130824 A1
  • Industrieverband Keramische Fliesen und Platten e.V. Ceramic Tiles EPD
  • M. Potter, "Feldspar and Nepheline Syenite," US Geological Survey Minerals Yearbook 2002
  • Matsumoto, Akio and Toshinya Nishikawa. "Vitreous china, method for preparing the vitreous china, sanitary-ware produced therefrom and glaze therefor." Toto Ltd., Assignee. Patent US5372976 A. December 13, 1994.
  • North Carolina Geological Survey: "Feldspar"
  • Office of Air Quality Planning and Standards, Economic Impact Analysis of the Clay Ceramics Manufacturing NESHAP: Final Rule, US Environmental Protection Agency, February 2003
  • Rio Tinto Minerals: "Borates in glazes and enamels" (undated)
  • Sectoral Life Cycle Analysis of Ceramic Tile
  • Torrecid Group - Czech Republic product page
  • US AID: "Privatization and Technical Assistance Program for the Kardzhali Region of Bulgaria" (1996)
  • US Patent: "Antimicrobial glaze and porcelain enamel via double layer glaze with high zinc content," American Standard (2006)