the historical hygiene assessment of national semiconductor uk

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WORKING FOR A HEALTHY FUTURE INSTITUTE OF OCCUPATIONAL MEDICINE . Edinburgh . UK www.iom- world.org A Review of the United Kingdom Historical Hygiene Assessment (HHA) of National Semiconductor UK John W Cherrie and Karen Galea

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Page 1: The Historical hygiene assessment of National Semiconductor UK

WORKING FOR A HEALTHY FUTURE

INSTITUTE OF OCCUPATIONAL MEDICINE . Edinburgh . UK www.iom-world.org

A Review of the United Kingdom Historical Hygiene Assessment (HHA) of National Semiconductor UK

John W Cherrie and Karen Galea

Page 2: The Historical hygiene assessment of National Semiconductor UK

Acknowledgements

• Work funded by the Health and Safety Executive (HSE)

• Part of an updated mortality study and “cluster analysis”• Principal Investigator Dr John Osman• Other collaborators: Brian G. Miller, Laura MacCalman,

Sam Wilkinson, Andrew J. Darnton, Amy Shafrir, Damien M. McElvenny

Page 3: The Historical hygiene assessment of National Semiconductor UK

Summary…

• The main stimulus for the study• Outline of the plant history• Key processes carried out• Gender differences in exposures• Key exposures of interest• The results from the epidemiological

investigations

Page 4: The Historical hygiene assessment of National Semiconductor UK

The stimulus for the study…

• Phase II pressure group• Results form a previous cohort

study undertaken by HSE• 11 female lung cancers

4 expected• 3 female stomach cancers

<1 expected• 4 male brain cancers

<1 expected• 20 female breast cancers

15 expected

Page 5: The Historical hygiene assessment of National Semiconductor UK

NSUK, Greenock, Scotland

• Wafer fabrication started in the early 1970s• Many individuals from the local area employed in plant

4547 employed before the end of

April 1999

Page 6: The Historical hygiene assessment of National Semiconductor UK

Methodology…

• Interviews with long-service employees and former employees• Nominated by company and pressure group

• Scrutiny of records, blueprints etc• Occupational hygiene measurement data• Details of ionising and non-ionising radiation sources• Details of Personal Protective Equipment (PPE) /

Respiratory Protective Equipment (RPE)• Smoking / health surveillance policies• Accident / incident reports• Shift pattern records

Page 7: The Historical hygiene assessment of National Semiconductor UK

Plant history…

Page 8: The Historical hygiene assessment of National Semiconductor UK

Possible exposure hazardous agents

• Shift work • Ionising and non-ionising radiation sources• Toxic metals • Toxic gases• Sulphuric and other acid mists• Various organic solvents• Asbestos (in buildings) and ceramic fibre

Page 9: The Historical hygiene assessment of National Semiconductor UK

Gender differences…

• Originally all operators were female• The first male operators began in the mid-

1980s By the mid-1990s when there was equal numbers of males and females

• Supervisory, maintenance, lab technicians and engineering were predominantly male

• In the early-1990s in Fab 2, men worked on processes where propylene glycol methyl ether acetate was used

Page 10: The Historical hygiene assessment of National Semiconductor UK

Shift work…

Page 11: The Historical hygiene assessment of National Semiconductor UK

Ionising radiation

• Variety of sources, including sealed sources, high voltage x-ray sources and Krypton-85

• In 1983 tracer flow/leak test process started• Same year the dose rates from process exceeded

legal limits (Kr-85)• Additional shielding• In 1984 process redesigned

• 1986 further problems with Kr-85 imregnating o-ring seals

• 1990 process discontinued

Page 12: The Historical hygiene assessment of National Semiconductor UK

Antimony and arsenic

• Antimony used in diffusion furnace operations• Measurements in 1982 showed levels well below OEL

• Arsenic used in diffusion furnaces, ion implanters (arsine), epitaxial reactors (arsine), vapour deposition reactors • Monitoring during process operations below OEL• Some maintenance tasks resulted in exposures above

OEL, but respirators used

Page 13: The Historical hygiene assessment of National Semiconductor UK

Results from the epidemiological study

• SMRs for the three cancers of prior interest for women reduced in new follow-up

• No further brain cancers in men• Poor response rate from

subjects/proxies in cluster analysis• No consistent evidence that cases

more likely to be exposed to hazards than controls

Page 14: The Historical hygiene assessment of National Semiconductor UK

Public response

Page 15: The Historical hygiene assessment of National Semiconductor UK

Further information at…

• Leaflet summarising the findings of the follow-up study

• Main report for the follow-up study • Appendices to the main report • Detailed Historical Hygiene Assessment

• www.hse.gov.uk/statistics/publications/nsuk.htm