Occupational Chemical Exposure Surveillance: Design and Validation

of a Survey

Rukmani Ramaprasad, MSc, MS

Lisa Huguenin, PhD

Paula Knudson, MS, CIH

Eileen Senn, MS, CIH

David Valiante, MS, CIH

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Research Funding

This study on exposure surveillance methodology was funded by the National Cancer Institute through NIOSH’s National Occupational Research Agenda (NORA)

Three-year study began October 1999

Research staff include in-house research scientists and consultants on survey design, statistics, and scanning software

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Occupational Chemical Exposure: Why Survey?

Timely & cost effective - Occupational exposure assessment through personal and/or area monitoring is costly and time consuming. Methods to estimate exposure for worker population in timely & cost effective manner are needed to prevent occupational chemical exposure.

Estimate exposure hazard - This research focuses on developing a survey to mail to employers to estimate exposure hazard or the potential for worker exposure.

Initiate primary prevention - The estimates derived from the survey could be used to engage in primary prevention activities at selected workplaces by mitigating or eliminating exposure.

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Research Aims:Design and Validation of a Survey

Design survey to learn how targeted chemicals are handled at specific workplaces and characterize exposure hazard

Validate and audit survey responses

Develop scoring method to rank workplaces based on exposure hazard

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Selection of chemicals

six known or probable human carcinogens

Selection of industries

Standard Industrial Classification (SIC) codes based on where the selected chemicals are likely to be handled

Survey Design: Key Elements

o cadmium

o ethylene oxide

o formaldehyde

o lead

o methylene chloride

o crystalline free silica

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Survey Design: Types of Industries/ Chemicals Targeted

Industry Chemical(s) Targeted

Primary metal, pigments, non-ferrous foundries

Lead, cadmium

Solvents, paint remover, rubber

Methylene chloride

Pottery, brick, tile, refractory, concrete, abrasives

crystalline free silica

Health care and surgical supplies

Formaldehyde, ethylene oxide

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Survey Design: Sample Selection

New Jersey workplaces that may use one of the targeted chemicals is identified from MarketPlace, a national database of businesses. Workplaces with one employee are excluded.

A stratified random sample of workplaces is selected using size of workforce as strata. Each workplace is selected for only one chemical. Final survey will be sent to 700 workplaces.

A random sample of respondents will be selected to audit and validate responses on-site

Survey Design:Key Survey Questions

Is the chemical handled?

What is the quantity of the chemical handled?

How is the chemical handled?

What are the patterns of handling?

How many workers handle the chemical?

What are their job titles and duties?

Are controls to reduce exposures in place?

The survey questions address the three routes of exposure – inhalation, ingestion and dermal contact and exposure control mechanisms in place.

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Chemical Exposure Surveillance:Research Methods

Develop & pre-test Chemical Survey design

Develop & pre-test on-site validation methods

Develop & pre-test scoring system

Mail final version of survey to 700 workplaces Conduct on-site validation and audit of a sample

of survey respondents

Score final version survey responses

Survey: Pre-tests

Evaluate survey design Do employers understand the study’s objectives? Are instructions and questions clear and easy to read? Is the order of the questions logical?

Evaluate protocol Are procedures practical and useful? Can deadlines be met?

Evaluate employer cooperation Do employers complete and return survey?

Three rounds of pre-tests have been conducted to evaluate and improve the survey based on telephone follow up of respondents and non-respondents.

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Pre-tests: Response Rates

Pre-test

Number of Workplaces

Surveyed Response Rate1st 38 77%

2nd 50 44%

3rd 116 17%

4th 80 Pending

Survey: Key Revisions

Narrowed selection of chemicals From original 34 carcinogens To six – many OSHA 6B chemicals not in use

Changed source for identification of workplaces From workplaces reporting chemical use in the New

Jersey Right to Know database To those in selected SIC codes from MarketPlace

database Changed “chemical use” questions

From: “Is chemical produced or used?”Answer - Yes or No

To: “How is lead typically handled at this worksite?”Answer - Yes or No to 17 statements

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Survey: Key Revisions (cont’d) Survey Packet - 1st Pretest

2 cover letters, suggested steps, FAQs, 3 survey forms (37 questions total)

Survey Packet - 4th Pretest Brochure with Confidentiality Statement Instruction sheet Chemical Survey (39 questions) Participant Form (12 questions)

Survey formatted for use with scanning software (Cardiff Teleform™)

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What’s Next?

Pre-test on-site validation and audit methods Select sample of 700 employers and conduct

final survey Select random sample of respondents and

conduct on-site validation

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Challenges Ahead

Survey Survey is not mandatory Must rely on employer cooperation Can’t offer financial incentives Balance number of questions vs.employers’ time

On-site validation Gain employers’ cooperation for on-site visit Finalize method to determine validity of responses