Performing Environmental Health Surveillance
12%of exam
Conducting Inspections
48%of exam
Conducting Investigations
18%of exam
Conducting Compliance Review
12%of exam
Providing Environmental Health Information
10%of exam
Quick Facts
- Credential
- NEHA REHS/RS
- Scope
- National credential exam
- Questions
- 225 multiple choice
- Scored
- 200 questions
- Pilot
- 25 unmarked questions
- Parts
- 113 plus 112 questions
- Testing Time
- 3 hours 40 minutes
- Break
- 10 minutes between parts
- Passing Score
- 650 scaled; not percent
Incidence vs Prevalence
Incidence
- New cases
- Population at risk
- Measures occurrence
Prevalence
- Existing cases
- Total population
- Measures burden
New flow vs existing pool
Surveillance Cycle
- Objective
- Define the decision need
- Case definition
- Standardize who counts
- Indicator
- Measure status or change
- Data source
- Match source to objective
- Collection
- Use consistent procedures
- Analysis
- Summarize person, place, time
- Interpretation
- Compare patterns and baselines
- Action
- Apply and evaluate controls
Epidemiology Math
- Incidence proportion
- New cases / population at-risk
- Prevalence
- Existing cases / population
- Attack rate
- Ill / exposed × 100
- Relative risk
- Attack exposed / attack unexposed
- Odds ratio
- Cross-products: ad / bc
- Sensitivity
- TP / (TP + FN)
- Specificity
- TN / (TN + FP)
- Case fatality
- Deaths / cases × 100
Sampling and QA
- Representative sample
- Reflects target population
- Random sample
- Known selection chance
- Chain of custody
- Documents possession and transfer
- Calibration
- Compare against known standard
- Field blank
- Detects field contamination
- Duplicate
- Checks sampling precision
- Accuracy
- Closeness to true value
- Precision
- Repeatability of measurements
Hazardous Waste ICRT
Ignitable | Corrosive | Reactive | Toxic
Ignitable: readily catches fireCorrosive: extreme pHReactive: unstable reactionToxic: leachable contaminants
Cleaning vs Sanitizing
Cleaning
- Removes soil
- Uses detergent action
- Comes first
Sanitizing
- Reduces microorganisms
- Needs correct contact
- Follows cleaning
Remove soil before reducing microbes
Inspection Response
- Imminent health hazard?→Apply emergency authority
- Immediate correction possible?→Verify correction onsite
- Violation remains?→Document requirement and deadline
- Repeat noncompliance?→Escalate consistently
- Correction reported?→Verify with evidence
Inspection Workflow
- Pre-inspection
- Review history and authority
- Equipment
- Calibrate before field use
- Opening conference
- State scope and purpose
- Observation
- Follow process and product
- Measurement
- Use verified instruments
- Documentation
- Record objective evidence
- Corrective action
- Match risk and authority
- Closing conference
- Explain findings and deadlines
Inspection Five
Review | Observe | Measure | Document | Correct
Review authority and historyObserve actual operationsMeasure with calibrated toolsDocument and verify correction
MCL vs MCLG
MCL
- Legally enforceable
- Accounts for feasibility
- Public water standard
MCLG
- Health-based goal
- Not enforceable
- Sets desired protection
Standard vs health goal
Food Controls
- Cold holding
- 41°F or below
- Hot holding
- 135°F or above
- Cooling stage one
- 135°F to 70°F; two hours
- Cooling total
- 135°F to 41°F; six hours
- Reheat for holding
- 165°F within two hours
- Date marking
- Seven days at 41°F
- Cross-contamination
- Separate raw from ready-to-eat
- Sanitizing
- Reduce organisms after cleaning
Cross-Connection vs Backflow
Cross-connection
- Physical link exists
- Creates contamination pathway
- Prevent by separation
Backflow
- Flow actually reverses
- Pressure difference drives it
- Protect with approved device
Pathway vs reverse movement
Water and Wastewater
- MCL
- Enforceable contaminant limit
- MCLG
- Nonenforceable health goal
- Turbidity
- Cloudiness; treatment performance signal
- Coliforms
- Microbial indicator organisms
- Cross-connection
- Potable-to-contaminant physical link
- Backsiphonage
- Negative pressure reverses flow
- Backpressure
- Downstream pressure reverses flow
- Sanitary survey
- System vulnerability evaluation
RCRA vs CERCLA
RCRA
- Ongoing waste management
- Generation through disposal
- Cradle-to-grave controls
CERCLA
- Hazardous release response
- Contaminated-site cleanup
- Liability framework
Manage waste vs clean releases
Onsite Wastewater Systems
- Septic tank
- Settles solids; stores sludge
- Baffle or tee
- Controls inlet and outlet flow
- Effluent filter
- Retains suspended tank solids
- Distribution box
- Divides flow among laterals
- Soil absorption
- Treats and disperses effluent
- Biomat
- Biological interface layer
- Hydraulic overload
- Flow exceeds system capacity
- Surfacing effluent
- Failure requiring prompt action
Recreational and Built Facilities
- Free chlorine
- Available disinfectant residual
- Combined chlorine
- Chloramine-associated residual
- Total chlorine
- Free plus combined chlorine
- pH
- Controls chlorine effectiveness
- Turnover time
- Volume / flow rate
- Entrapment control
- Protect suction outlets
- Healthy housing
- Dry, clean, ventilated, pest-free
- Institution inspection
- Evaluate vulnerable-population safeguards
Facilities and Waste
- RCRA
- Active waste management framework
- CERCLA
- Release response and cleanup
- Ignitability
- Hazardous waste characteristic
- Corrosivity
- Hazardous waste characteristic
- Reactivity
- Hazardous waste characteristic
- Toxicity
- Hazardous waste characteristic
- Biomedical waste
- Segregate at generation
- Integrated pest management
- Prevent, monitor, control, evaluate
Risk Assessment Four
Hazard | Dose | Exposure | Characterize
Hazard: identify harmDose: link dose-responseExposure: quantify contactCharacterize: integrate uncertainty
Hazard vs Risk
Hazard
- Inherent harm potential
- Agent or condition
- Exists without exposure
Risk
- Probability and consequence
- Depends on exposure
- Includes uncertainty
Potential harm vs realized likelihood
Outbreak Investigation Path
- Excess illness suspected?→Confirm diagnosis and baseline
- Outbreak exists?→Define and find cases
- Cases assembled?→Describe person, place, time
- Pattern suggests exposure?→Develop testable hypothesis
- Hypothesis supported?→Trace source and control
- Controls implemented?→Evaluate and communicate
Outbreak Investigation
- Confirm diagnosis
- Review clinical and laboratory evidence
- Confirm outbreak
- Compare observed with expected
- Case definition
- Clinical, person, place, time
- Line list
- One row per case
- Epi curve
- Cases by onset time
- Hypothesis
- Testable exposure explanation
- Traceback
- Follow product distribution chain
- Control measures
- Interrupt exposure or transmission
Descriptive Epidemiology
Person | Place | Time
Person: affected groupsPlace: geographic patternTime: epidemic curveTogether: generate hypotheses
Risk Assessment
- Hazard identification
- Can the agent cause harm?
- Dose-response
- How dose changes effect
- Exposure assessment
- Who, how much, how long
- Risk characterization
- Integrate risk and uncertainty
- Exposure route
- Inhalation, ingestion, dermal
- Sensitive population
- Greater susceptibility or exposure
- Risk management
- Choose and implement controls
Vector and Indoor Air
- Vector surveillance
- Track species and abundance
- Source reduction
- Remove breeding habitat
- Reservoir
- Maintains agent in nature
- Moisture
- Primary mold-growth control
- Carbon monoxide
- Combustion gas; impairs oxygen delivery
- Ventilation
- Dilutes indoor contaminants
- Complaint history
- Guides inspection scope
HACCP Seven
Hazards | CCPs | Limits | Monitor | Correct | Verify | Record
Analyze significant hazardsControl at critical pointsMonitor measurable limitsCorrect, verify, document
Verification vs Validation
Verification
- System follows plan
- Records and calibration
- Ongoing confirmation
Validation
- Controls can work
- Scientific or technical basis
- Established before reliance
Doing it right vs effective
HACCP Control Decision
- Significant hazard present?→Identify preventive control
- Step controls hazard?→Evaluate as CCP
- CCP confirmed?→Set measurable critical limit
- Limit can drift?→Define monitoring
- Deviation occurs?→Apply corrective action
- System operates?→Verify and retain records
HACCP Seven Principles
- Principle 1
- Conduct hazard analysis
- Principle 2
- Determine critical control points
- Principle 3
- Establish critical limits
- Principle 4
- Establish monitoring procedures
- Principle 5
- Establish corrective actions
- Principle 6
- Establish verification procedures
- Principle 7
- Establish records and documentation
Plan and Compliance Review
- Plan review
- Prevent problems before construction
- Flow diagram
- Trace process and hazards
- Critical limit
- Measurable CCP boundary
- Variance
- Approved departure from rule
- Permit status
- Verify authority to operate
- Compliance evidence
- Records, observation, measurement
- Technical assistance
- Explain compliant control options
Enforcement Ladder
- Education
- Clarify requirement and risk
- Correction
- Remove immediate violation
- Written notice
- Document violation and deadline
- Reinspection
- Verify sustained compliance
- Administrative action
- Escalate under governing authority
- Due process
- Notice and hearing opportunity
- Consistency
- Apply policy uniformly
NEHA Credential vs State License
NEHA REHS/RS
- National credential
- NEHA eligibility
- Current five-domain outline
State credential
- Jurisdiction-specific authority
- State eligibility
- May use different exam
Confirm governing credential first
Public Message Selection
- Immediate action needed?→Lead with protective action
- Evidence incomplete?→State uncertainty plainly
- Audience is technical?→Add methods and limits
- Audience is public?→Use plain language
- Message released?→Monitor understanding and update
Risk Communication
- Audience
- Identify needs and concerns
- Core message
- State risk and action
- Plain language
- Use familiar concrete terms
- Uncertainty
- Acknowledge what remains unknown
- Empathy
- Recognize concern before facts
- Consistency
- Coordinate messages across partners
- Feedback
- Check understanding and response
Emergency Information
- Preparedness plan
- Define hazards, roles, resources
- Incident command
- Scalable response structure
- Unified command
- Shared authority across agencies
- Situation report
- Current facts and actions
- Public advisory
- Specific protective action
- Recovery
- Restore and monitor services
- After-action review
- Capture gaps and improvements
Common Traps
Old Blueprint vs Current
Current outline has five domains ≠ Do not use six-domain brochure
Total vs Scored
Exam presents 225 questions ≠ Blueprint allocates 200 scored items
Scaled vs Percent
Passing scaled score is 650 ≠ It is not 65 percent
Model Code vs Local Law
FDA Food Code is model guidance ≠ Jurisdictions adopt enforceable versions
Inspection vs Investigation
Inspection checks regulated conditions ≠ Investigation resolves cause or complaint
Negative Sample vs Safety
Sampling covers limited material ≠ Negative result proves no universal absence
Correlation vs Causation
Association can support hypotheses ≠ Causation needs converging evidence
Correction vs Compliance
Immediate correction removes condition ≠ Compliance prevents recurrence
Disinfectant vs Clarity
Clear water can remain unsafe ≠ Verify chemistry and treatment
Message Detail vs Action
Protective action comes first ≠ Technical detail follows audience needs
Last Minute
- 1.National NEHA credential; not state variant
- 2.225 total; 200 scored; 25 pilot
- 3.Parts: 113 plus 112 questions
- 4.Time: 110 minutes each part
- 5.Break: 10 minutes
- 6.Passing score: 650 scaled
- 7.Surveillance: 12%; 24 scored items
- 8.Inspections: 48%; 96 scored items
- 9.Investigations: 18%; 36 scored items
- 10.Compliance review: 12%; 24 scored items
- 11.Information: 10%; 20 scored items
- 12.Food Code edition: 2017
- 13.Cold ≤41°F; hot ≥135°F
- 14.Cooling: 135→70°F within two hours
- 15.Cooling: 135→41°F within six hours
- 16.Attack rate = ill / exposed
- 17.Hazard, dose-response, exposure, characterization
- 18.HACCP: seven ordered principles
- 19.Document objective inspection evidence
- 20.Lead public messages with action
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