Occupational Chemical Exposure Surveillance: Design and Validation of a Survey

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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 NIOSHs 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 AimsDesign 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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Survey Design Key Elements

• 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

• cadmium
• ethylene oxide
• formaldehyde
• lead
• methylene chloride
• 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

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

• 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?

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Chemical Exposure SurveillanceResearch 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

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

• Evaluate survey design
• Do employers understand the studys 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?

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Pre-tests Response Rates
Pre-test Number of Workplaces Surveyed Response Rate
1st 38 77
2nd 50 44
3rd 116 17
4th 80 Pending
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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 (contd)

• 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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Whats 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
• Cant 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