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Lead danger in pottery

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The Commonwealth Director-General of Health, Sir William Refshauge, warned today of a possible health hazard associated with the use of certain types of imported pottery and chinaware because of a high content of leachable lead in the glazes used on these items. j

Sir William said that lead was a recognised cumulative poison ; to man and the continued use of such pottery and china presented a ' hazard to human health. The products referred to by Sir William are all from China and carry no brand name, manufacturer's name or patent number, and the only identification is "Made in China".

Sir William said that.the Department of Customs and Excise has taken action to have the importation of pottery, porcelain and china- ware which could release more than seven parteper million of lead . . under certain conditions of use prohibited. He-said this action had been taker

because tests on some imported articles had shown a leachable lead . content far in excess of this level. '

Sir William said that the. National Health and Medical Research Council had in November 1971 after receiving the report' (1) of its Occupational Health Committee made the following recommendation in relation to Lead Hazards from Pottery Glazes:

Council considered that pottery utensils with glazes which / release seven parts per million more of lead, as determined by the / ASTM method, C-555-71· 'Estimation of Lead Extracted from Glazed Ceramic Surfaces', are unsafe for use as human food or drink . containers. Council therefore recommended that:

(i) legislation be enacted by the Commonwealth and the States to prohibit the sale of pottery food and drink utensils which may, by the release of lead, be hazardous to human health;

(ii) glazing formulations containing lead which are available in Australia should be labelled 'WARNING - this glazing material . contains lead';

(iii) amateur or handicraft potters should not apply glazes bearing >_ lead to the insides of food and drink utensils unless they are able to ensure that the techniques they employ preclude ' the subsequent release of unsafe amounts of lead from the

glaze; and -

(iv) acidic foods and beverages should not be stored in pottery containers unless the containers are known not to release significant amounts of lead.


Sir William said that following this recommendation, the National Health and Medical Research Council had asked the Department of Customs and Excise to conduct a .survey on items of imported pottery and china to establish whether a danger existed. The survey had not revealed any items having significant readings until recently when a number

of samples drawn from consignments of crockery from China had shown elevated leachable lead contents.

Sir William said that the Department of Customs and Excise had informed him that quantities of crockery from the same 'source had been released from Customs control for distribution throughout Australia prior to the detection of the high lead content of the glazes. State Health Departments had been notified of the matter.

Sir William said that holloware crockery (i.e. cups, bowls, jugs etc.) should not be used to contain foods and beverages, particularly those which are acidic such as fruit juice, carbonated beverages, wines, cider, tea, coffee, all foods containing vinegar,

sauerkraut, tomato products, cooked fruits and fruit products. .

Sir William said he proposed to ask the National Health and Medical Research Council to institute a national surveillance ■ programme on glazing techniques, testing and certification of both imported and domestically produced pottery.

He pointed out that health problems associated with the leaching of lead pottery glazes have been shown to constantly recur since ancient times. '

(1) The report of the Occupational Health Committee of the National Health and Medical Research Council (Agenda Item 3.13) August 1971 as attached. ■

National Health and Medical Research Council

Occupational Health Committee, August 1971

Lead Hazards from pottery glazes

At its last meeting in February 1971 the Committee noted the reference in the New England Journal of Medicine, Vol. 283, No. 13 p. 669 and considered a paper submitted by the Chairman on the above topic. This paper reported information provided by Mr Rushforth of the Ceramic Study Group, East Sydney,Technical


(i) Apart from the State regulations on lead, no controls or legislation exist concerning glazes. There is a British Standard relating to the glazing frits that contain lead. The clay, slate etc. are fired with the lead compounds to produce a type of glass in which lead is practically insoluble' in potable liquids or foodstuffs. In N.S.W. there is one large company·whose staff are well aware of the hazards and take great care with the frits. However, ■ ■ ■ there are some others who are not very concerned

with the quality of their glazing materials.

• (ii) It is estimated that in N.S.W. there are at least 5,000 amateur potters, and the Ceramic Study Group has some 600 members. Full-time courses are held in Sydney, Newcastle and other country centres; pottery

is taught to certain students in almost every High School in N.S.W. ·

(iii) It is common knowledge among amateur potters that red lead, litharge or white lead can be used for glazing, and the lead compounds can be purchased in many hardware shops. '

(iv) In addition to the "regular" kilns (fired at 1050- 1100°C), there are low-temperature kilns in which the articles are pre-heated, removed whilst hot, coated with "raw" lead (litharge or lead carbonate) and returned to the furnace for firing. The temperatures are not sufficiently high to permit complete fusion of the lead with silica, and a considerable amount can be leached from the surface by means of dilute acid. The low-temperature method stems from Japan. ' Under existing legislation, no checks are necessary to ascertain how much lead can be leached by.

foodstuffs or beverages.

It was also reported that one important aspect which needs investigation is the danger of low-fired lead-glazed earthenware being used for domestic ware. There appears no routine check, as carried out in Great Britain, whereby earthenware is tested by Health Department officials for lead solubility. '

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Another factor reported was that it is possible that not only local pottery, particularly that made by amateurs, but also imported pottery, could be glazed with a glaze that is a health hazard. Many "Art Glazes" could be suspect, even though they are glazed with a fritted glaze. In the case of raw lead glazes, should they be fired at low temperatures the lead may not have

formed a silicate, and will therefore remain as lead in a matrix of silica, this is often the case with "Raku" ware.

The Chairman suggested that a need existed for control in Australia on the composition of imported and locally produced glazes as well as a requirement to check the finished articles in order to determine the amount of lead which can be extracted by acidic substances. The Committee after considering such

matters agreed that the subject was of direct interest to the Public Health Advisory Committee. The Committee further agreed that members should investigate the situation in their own areas,

collect information and report back at the next meeting in order that the Committee could deliberate on appropriate action.

The Committee was advised that at its meeting in May 1971 the Public Health Advisory Committee noted that it appeared that there was some likelihood of potential hazard from some pottery glaze. The PHAC also noted that the Occupational Health Committee was investigating this matter and requested the Occupational Health Committee to prepare a warning statement on this matter for circulation to the States and to also further

investigate the problems involved. ·

Other articles noted by the Committee were:

A report with relevant Annexures prepared by the Scientific Attache of the Australian Embassy in ' Washington. This is the report of a meeting convened by the II. S. Food and Drug Administration in April;

An article from Pottery in Australia (Vol. 10, No. 1 1971) which comments on the N.E.J.M. article of September 1970;

An article from California's Health, February 1971 entitled:‘Acid foods remove lead glaze from some · pottery;0

A HEW News which dealt with the hazard of lead in decals used to decorate ceramic dinnerware; and

A report entitled, "Lead Hazards from Pottery Glazes", prepared by the Occupational Health ■ Section, School of Public Health and Tropical ■ Medicine. .


British Standard Specification, Metal Release from Glazed Ceramic 'Tableware British Standards Institution, Document No. 71/61033·

Report by the United States Potters Association "Dinnerware Glaze Surveillance Programme".

The Committee agreed that in view of the evidence submitted, a definite hazard existed in the use of utensils as food and drink containers, which had been incorrectly glazed with lead bearing glazes.

Dept. No. 11 9 Canberra, December 15, 1972.