Zirconium dioxide

Direct observations: clinical cases, poisoning incidents and other

Administrative data

Endpoint:

direct observations: clinical cases, poisoning incidents and other

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Case study of a 62 years old man. Material safety datasheets obtained from the company indicated that the patient had been exposed to a number of compounds, including talc, zinc stearate, iron compounds, asbestos, aluminum oxide, silica, zirconium oxide, and traces of other metals. In addition, the patient smoked. Overall, it is difficult to clearly attribute the observed effects to zirconium exposure (as 90% zirconium oxide and 10% "respirable quartz". In addition, there was no information on the exposure levels on the workplace of the patient.

Data source

Reference

Reference Type:

publication

Title:

Zirconium Compound-Induced Pulmonary Fibrosis

Author:

Bartter, T., Irwin, R.S., Abraham, J.L., Dascal, A., Nash, G., Himmelstein, J., Jederlinic, P.J.

Year:

1991

Bibliographic source:

Archives of Internal Medicine 151, 1197-1201

Materials and methods

Study type:

clinical case study

Endpoint addressed:

repeated dose toxicity: inhalation

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Zirconium dioxide

EC Number:

215-227-2

EC Name:

Zirconium dioxide

Cas Number:

1314-23-4

Molecular formula:

O2Zr

IUPAC Name:

zirconium dioxide

Details on test material:

- Name of test material (as cited in study report): Zirox B with a chemical composition of 90% zirconium as zirconium oxide and 10% "respirable quartz".

Method

Subjects:

A 62-year old man with a chief complaint of dyspnea that had increased gradually during the preceding 25 years. Twenty-five years earlier, he had seen a physician for a complaint of dyspnea and had been told that he had emphysema and needed to stop smoking. He did stop, having smoked two packs a day for the preceding 20 years. His dyspnea, nonetheless, gradually increased. Ten years before the current examination, he had again sought medical care for his dyspnea and again had been told that he had emphysema. No specific therapy was given. He had no other medical problems and was never taking any medications. The patient had never had pulmonary function tests before; early diagnoses had apparently been based on his smoking history and his symptoms. How roentgenographic abnormalities had been interpolated into the diagnosis is unclear. From the patient's medical history, no evidence could be found that the home environment involved exposure to any agent capable of causing hypersensitivity pneumonitis. The patient had worked at various odd jobs until the age of 22 years. He had begun to work at the lens-grinding department of an optical company in 1946, at the age of 24 years, and had continued to work there until retirement 39 years later. At the optical company, he had been involved in the grinding, polishing, pitting, and blocking of lenses. Material safety datasheets obtained from the company indicated that the patient had been exposed to a number of compounds, including talc, zinc stearate, iron compounds, asbestos, aluminum oxide, silica, zirconium oxide, and traces of other metals. The patient had never worn a mask when at work. According to the patient, his greatest dust exposures had taken place during the blocking operation, which involved the use of talc powder, and the polishing operation, which involved the use of a compound called Zirox B.

Route of exposure:

inhalation

Reason of exposure:

unintentional, occupational

Exposure assessment:

not specified

Results and discussion

Clinical signs:

This patient had a progressive, prolonged decline in functional status that had been misdiagnosed clinically as emphysema; when studied objectively, pulmonary function tests, chest roentgenograms, and lung tissue documented interstitial fibrosis and restriction without obstruction.

Any other information on results incl. tables

The presence of severe pulmonary fibrosis in a man with a history chest roentgenograms documenting slow progression of disease over many years. Salient in his workup were the presence of markedly elevated levels of zirconium in lung tissue and the absence of evidence of another cause of pulmonary fibrosis. The case reported suggests that zirconium should be considered a possible cause of pulmonary fibrosis and that appropriate precautions should be taken in the workplace wherever and whenever workers are exposed to zirconium. Unfortunately, there was no information on exposure levels in the workplace of the patient and no comment was made on the adequacy of the permitted levels of exposure to zirconium.

Applicant's summary and conclusion

Conclusions:

The publication reported a case study of a 62 years old man with pulmonary fibrosis. Material safety datasheets obtained from the company indicated that the patient had been exposed to a number of compounds, including talc, zinc stearate, iron compounds, asbestos, aluminum oxide, silica, zirconium oxide, and traces of other metals. In addition, the patient smoked. Overall, it is difficult to clearly attribute the observed effects to zirconium exposure (as 90% zirconium oxide and 10% "respirable quartz"). In addition, there was no information on the exposure levels on the workplace of the patient. Based on these criteria, it can be concluded that the data provided in the publication are not reliable.