Background Paper for Evaluating the Use of Cathode Ray Tube
(CRT) Glass as a Substitute for Lead Oxide in Ceramic Tile
Manufacturing
January 20, 2016
Introduction
On September 10, 2014, EPA issued a letter regarding the use of CRT funnel glass as a substitute for
lead oxide in the production of ceramic tiles.1 CRT funnel glass may be excluded from the Resource
Conservation and Recovery Act (RCRA) hazardous waste regulations under the "use/reuse'' exclusion
(40 CFR 261.2(e)) for hazardous secondary materials used as an ingredient to make 3 product or used
as an effective substitute for a commercial product, as long as that use is legitimate, This paper-
provides background information that EPA considered in developing that letter.
Note that EPA has no specific testing requirements for products made from recyclable hazardous
materials. In order to be legitimate recycling, one of the factors that must be met is that products
from the recycling process must be comparable to legitimate products (see 40 CFR 260.43(a)(4)).
However, a generator can use any number of methods for making this determination, including using
generator knowledge or widely-recognized specifications that address the hazardous constituents, to
determine that the product of recycling is comparable to a legitimate product. It is the generator's
responsibility to make the determination of legitimate recycling if claiming a recycling exclusion from
the regulations, and no prior approval from EPA is required.
In addition, under Section 3006 of the Resource Conservation and Recovery Act (RCRA) individual
states can be authorized to administer and enforce their own hazardous waste programs in lieu of the
federal program. Under Section 3009 of RCRA, states retain authority to promulgate regulatory
requirements that are more stringent than the federal regulatory requirements. Generators should
consult with their authorized state agency when making a legitimate recycling determination.
Finally, it should be noted that the use/reuse exclusion would only apply to the processed CRT glass
that is legitimately used as an ingredient to make a product or as an effective substitute for a
commercial product. CRTs themselves (whether intact or broken) would continue to be regulated
under the CRT rule (found at 40 CFR 261.4(a)(22)) or as hazardous waste.
Legitimacy Factor 1: Does the CRT funnel glass provide a useful contribution?
EPA F inding: CRT funnel glass can provide a useful contribution both to the recycling process (firing
of ceramics) as well as to the product of the recycling (ceramic tile and glaze).
' U.S. EPA (2014). Memo from Barnes Johnson, Director, Office of Resource Conservation and Recovery to Chris York, Sims
Recycling Solution, September 10, 2014, RCRA Online ! 484i>.
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The use of lead in ceramics has an extensive history and lead is a valuable component of many glasses
and glazes. Lead compounds, such as lead oxide (PbO), have historically been used in glaze
formulations to regulate the melting properties of other glaze components and to enable the use of a
broad firing temperature range in the production process.
In this case, the lead oxide in the CRT glass acts as a flux in the manufacturing process and reduces the
energy needed for firing by approximately 10-15%. Additionally, the CRT glass substitutes for up to 15-
20% of rnw materials (e.g., silica, strontium, clay, feldspar, and barium} in the tiles and glaze.
Benefits of Using Lead Oxide in Ceramic Glaze
Some of the general characteristics of glazes made with lead oxide include:1
• low Melting Range, The strong fluxing action of PbO allows the formulation of glazes, which
mature at relatively low temperatures in comparison with their leadless counterparts.
• Wide Firing Range, PbO in the glaze reduces viscosity and allows for satisfactory maturation
over a wider firing range.
• Low Surface Tension. PbO imparts low surface tension, which is chiefly responsible for the
.smooth flow and generally high gloss of these glares. Low surface tension is the property that
contributes to the ability of lead glazes to heal over blisters, drying cracks, and other defects in
the glaze surface. Low interfacial tension contributes to the good wetting and adherence of the
glaze to the body. Low surface tension coupled with the wide softening range of lead glazes
accounts for their superior maturing qualities.
• High Index Of Refraction. Brilliant glaze surfaces are attained due to high index of refraction
imparted by PbO.
• Resistance to Devitrification. The presence of PbO in the glaze reduces any tendencies towards
surface crystallization or devitrification of the glaze. Devitrification is the process whereby the
surface of the glass develops a whitish scum, crazing (network of fine cracks), or wrinkles
instead of a smooth glossy shine, as the molecules in the glass change their structure into that
of crystalline solids
Comparison to Lead-less Giazes
Development of lead-less glazes began after World War II in response to shortages of lead oxide. More
recent emphasis on leadless glass and glaze development occurred in the 1980's and 90's as
environmental, occupational safety, and lead migration regulations became stricter, Three substitutes
for the use of lead have been pursued. Direct substitution of bismuth for lead produces adequate
• "h'.ul i"i C" f jiuj.v ir. Dr Richard Lehman, Rutgers University and The International lead Management
Center
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results. However, bismuth can impart a yellowish color under certain circumstances, the supply of
bismuth is limited, the price is high, and the toxicity of bismuth itself may be an issue. A second group
of leadiess compositions uses zinc and strontium to provide the necessary fluxing. These glazes are
giossy and fire well, but color development is poor. A third approach uses alkali borosilicate [ABS]
formulations. The ABS glazes are becoming widely used, particularly on bone china due to the high
expansion of the ware, but significant problems remain with its use. Higher firing temperatures are
required to produce a smooth glaze surface, the leadiess glazes react less aggressively at the body
interface, defect rates are higher, and decoration is difficult.'
Use of Lead Oxide in Ceramics Worldwide
Non-iead glazed ceramic ware is quite common in the U.S. due to the stricter FDA guidelines issued in
1992 for leachable lead from ceramic ware. It is not clear how common lead oxide is used in other
countries. It is likely that lead oxide use in Europe is becoming less common due to increasing
environmental restrictions imposed by the European Union (EU), The U.S. imports a significant amount
of ceramic ware from China and the lead glazed ware from China is subject to an MOIJ between the
two countries.
CRT Glass Recycled into Ceramic Tiles
The use of CRT glass in the manufacturing of tiles is the result of a number of European Union
initiatives designed to address the environmental problems associated with waste electrical and
electronic equipment (WEEE). This type of recycling was selected by the European Commission as a
y f under its LIFE + Programme for its potential environmental benefits and contribution to
sustainable development.
Legitimacy Factor 2: Are the ceramic tiles a valuable product?
EPA Finding: Ceramic tiles manufactured from processed CRT glass and sold to third parties for use in
walls and flooring would be considered a valuable product.
The ceramic tiles comply with the European standard (UNE-EN 14411:2007) for ceramic tiles.
Additionally, the ceramic tiles have been independently tested and their integrity verified by the
University of Casteilon.
The CRT glass recycler, in this case, a foreign entity, has developed four recipes for using CRT funnel
glass in ceramic tiles and provides the recipes, along with the prepared glass cuilet it sells, to a number
of ceramic tile manufacturers in countries such as Belgium, Germany, Great Britain, Greece, Holland,
Italy, and Portugal.
5 Lead Glazes, Dr. Lehman.
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The CRT glass recycler says they have 30-35 customers that currently purchase the prepared glass
cutlet at a rate of 9,000 tons per year. The ceramic tiles are then sold to markets around the world and
are used iri walls arid flooring for residential, commercial, and industrial areas.
Legitimacy Factor 3: Is the CRT glass managed as a valuable commodity?
EPA Finding: The CRT glass appears to be managed as a valuable commodity and managed to
minimize loss to the environment.
The CRT glass will be shipped in large Gaylord boxes that are shrink wrapped, which will minimize loss
to the environment. Both entities are certified to the International Standard Organization (ISO)
standards and the domestic electronics recycler meets third party recycling standards.
Legitimacy Factor 4: Do the ceramic tiles contain ''toxics along for the ride"?
EPA Finding: information provided by the recycler indicate that the concentrations of lead and
cadmium in the ceramic tiles are at levels that meet widely-recognized commodity standards and
specifications that address these constituents (i.e., permissible ievels set by the European Union (EU)
for ceramics intended to come into contact with food).
When glazes are properly formulated and fired at a high temperature, the lead is sealed or "vitrified."
However, if the glazes are not properly prepared and fired, lead may leach {i.e. move from the glaze)
into food stored in or on the ceramic ware. The problem of lead migration was recognized early in the
twentieth century and an increasing level of research was focused on fritting of lead oxides to reduce
the lead availability and on understanding the proper formulation of lead glazes to minimize migration
by interdiffusion. This effort culminated in the 1974 Geneva Conference on Ceramic Foodware Safety
at which state of the art technology was presented. The Conference also laid the groundwork for broad
international standards on the test methods and permissible limits of lead and cadmium release from
foodware surfaces.
Both the American Society for Testing and Materials (ASTM) and ISO standards prescribe a test method
for lead and cadmium extracted from glazed ceramic surfaces {ASTM C738 --94; ISO Standard 6488).
These ttests evaluate lead and cadmium released from the surface of glazed tiles over a 24 hour
exposure to a 4% acetic acid solution. The procedure of extraction may be expected to accelerate the
release of lead from the glaze and to serve, therefore, as a severe test that is unlikely to be matched
under the actual conditions of usage of such ceramic ware.
The CRT glass recycler states ceramic tiles made from their product contain "less than 0.001% lead"
and "do not leach," The lead is in the form of lead oxide and is vitrified with the rest of the final
product. The recycling process requires a firing temperature lower than 1,400°C and thus the lead will
not split from the oxygen.
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The CRT glass rccycler has submitted testing from UNE-EN ISO 10545-15 "Determination of the
emission of lead and cadmium in ceramic tiles." The CRT glass recycler says the levels of lead and
cadmium could not be detected arid reported their results as <0,004 mg/dm'' for lead and <0,002
mg/drrr for cadmium, (See attachment.)
Regulation of Ceramic Tiles in the European Union
Lead and cadmium in ceramic materials intended to come into contact with food are regulated by the
EU (Council Directive R4/S00/EECl_5, October 15,1934). This Directive sets migration limits for the
metals, which might be released from decoration or glazing, In addition, it prescribes an analytical
method for the determination of the migration of these two elements. The EU statutory limits for
Category 1 (non-fillable) ceramics are 0.8 mg/dm2 for lead and 0,07 mg/dnr' for cadmium.
Based on guidance from the European Food Safety Committee, the EU Commission has px?j3pAed to
reduce the permissible limits for the transfer of lead and cadmium from ceramic materials intended to
come into contact with food. Should the EU finalize changes to their limits, the ceramic tiles would
need to comply with the new limits.
The Table below compares the current EU statutory limits, the proposed EU statutory limits, and the
CRT glass recycler* $ test results.
Category 1
Ceramics (not
fillable
ceramics)
Lead
Cadmium
Current EU statutory
limits for ceramic
material intended to
come into contact with
food
0.8 mg/dm'
0.07mg/dm;
Proposed EU statutory
limits for ceramic material
intended to come into
contact with food
10.002 mg/dnv
0.001 mp,/dnr'
Test Results from CRT
Glass Recycler
<0.004 rng/dnr (Could not
be detected)
<0,002 mg/dm3 (Could not
I be detected)
Regulation of Ceramic Tiles in the United States
Unlike the European Union (EU), the United States does not set regulatory levels for lead that would
apply to ceramic tiles.4 The FDA does regulate the sale of tableware (plates, cups, pitchers) that
contain lead and tableware exceeding the FDA action levt-h cannot be sold legally in the U.S.5 The U.S.
Food and Drug Administration (FDA) states the problem is not that ceramics contain lead, but they
contain lead in a form that may leach into food.6
" The United Slates Consumer Product Safety Commission has banned lead in paint (197?) and toys {2008J, but these bans
do not apply to (jlases or ceramics.
- FDA CPG 'j4S-450 "Pottery (Ceramics); Import and Domestic - Lead Contamination," last updated November 2015.
FDA • m*i .i.inri 1 .'ini.it.•: "Some 'Lead-free' Pottery Can Still Taint food," November 2010.
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According to the FDA, proper firing of ceramics would typically vitrify lead in the glaze and limit any
potential for it to leach into food should the ceramic tiles have contact with food. FDA's standard is
based on reasonable expectation of migration under intended use conditions, in contrast to the EU ISO
standard leach test, which is considered an extreme "stress test" condition.
The FDA action levels for lead in ceramic ware are as follows;
Category Guidelines pg/mL {FDA 2000)
, Flatware ; 3.0
'
; Small Hollow/ware other than cups and mugs
Cups/mugs
large Hollowware other than pitchers
Pitchers
However, the results of the CRT glass recycler's test on the tiles cannot be directly compared to the
FDA action levels for ceramic ware to because the test is reported in mg/dnr1 (mass/area) and the FDA
action levels are in micro^rarns/mL (mass/volume). If the intended use of an article would be
reasonably expected lo result in its migration into food, the manufacturer would have to submit pre-
market notification to the FDA for assessment.
Export Regulations
Additionally, because CRT funnel glass managed under the "use/reuse exclusion" would not be RCRA
hazardous waste in the United States, the CRT glass would not be subject to notice and consent under
U.S. export regulations in 40 CFR part 262 subparts f or H. However, because CRT glass is a listed
hazardous waste under the Organization for Economic Cooperation and Development's (OECD}7
Council Decision it would be subject to applicable regulations in the countries of transit and import
implementing the OECD Council Decision, Under Section II,B.4 of the OECD Council Decision, if the
waste being shipped is controlled as hazardous by only one of the countries of export and import, then
the notice and consent procedures and other associated procedures are administered by the country
that controls the waste as hazardous. This is referenced in 40 CFR 262.82(a)(2)(iii).
2.0
0.5
1.0
0.5
' OECD Council Decision C (2001 j 107/FINAL on the Control of Transbourtdary Movements of Waste Destined for Recovery
Operations (CRT glass is listed as A2010, "Glass waste from cathode-ray tubes and other activated glasses"}.
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Attachment: Laboratory Test Results on Ceramic Tiles Manufactured Using CRT Glass
{In Spanish Followed by English Translation)
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CSIC .'{(if
LiBORA WRIO DEAX-UJMS Ql'LwiCO
ANAL1SIS QU1MK Q
FEC HA:
.V DE MUESTRAS:
DENOMTS'AC ION:
TEC MCAs EMPLEADAS;
PERSONA COMAC TO;
Of-06-2013
\
E.iklor.ns mnmic;*'. A, B. C
Espectroiiis-nm IC P-OES
F, Rubio
Los analisis de las baldosas deooiniaftdas A, B y C, se ban reafaado siguiendo la norma
UNE-EN ISO 10545-15 " Determination ie la mimSn de Plomo y Cadmio en las baldosas ceramtcas
El ensayo se ha llevado a cabo stoultaaeamente en sets probetas de cada una de las baldosas (A. B y C)
Se hamprepatado sets probetas de 7x7 an2, de cada una de las muestras. En cada una de ellas se ha aplicado
im cordon de silicona (fibre de Fb y Cd), alxededo; de todo d perimetro de ia saperficie esmaltada.
En cadi, una de las probetas se ha aficionado 35nl de acid© acetico al 4% y se la roantenido tapado durante
24 boras.
La d^emunacion del contenido de plomo y cadmio en las sofrtciones de esctraocioa se ha reaiizado
mediante la tecnica de espectrometria de plasma ICP-OES.
Los resattados coaespanden a la media de los 6 sisayos:
MUESTRA
Pb
(mg'cW)
Cd
(mg/dm2)
A
• 0.004
-• 0.002
D
D
0.004
•:'0.002
C
•¦-0.004
- 0 002
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Chemical Analysis
Date. June 5, 2014
Number of Sample: 3
TitSe: Baldosas ceramicas A, B. C
Ceramic Tiles A, B, C: Spectrometry 1CP-OES
Contact Person: F. Rubio
Analyses of tiles caf;ed A, B and C, were performed fol-cwtng the standard UNE-EN ISO 10545-15
Doterm nat on of the emission of lead and cadrraum in ceramic ti'ei:"
The test was earned out simu taneously in six samples of each of the tiles (A, 8 arrl C).
Su ten pieces were prepared 7*7 cm2, of each of the samples. In each of wh.ch is assigned a bead of
silicone [free of ?b and Cd), around the entire perimeter of the glssecl surface-. 'n each of the test
specimens »vas added 3S m, of A'—, acetic acid arid has been covered for 24 hours.
Determination of lead and cadmium in the extraction strutsoni was performed using the technique of
p ajrna spectrometry 1CF-DE5.
The results, are the mean of 8 trials;
Sample
PB
(mg/drnl)
Cd
(mg/dm2)
A
- 0.034
<0.002
8
<0.004
<0 002
C
<0.004
<0.002
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