Center for

Toxicology and Environmental Health (CTEH)

The 2014 Tank Vapor Assessment Report (TVAR), developed by the Hanford Tank Vapors Assessment Team and led by Savannah River National Laboratory (SNRL), provided an Overarching Recommendation to “accelerate development and implementation of a revised IH exposure assessment strategy that is protective of worker health and establishes stakeholder confidence in the results for acute as well as chronic exposures.” .


In April 2016, WRPS contacted the Center for Toxicology and Environmental Health, LLC (CTEH), a nationally recognized industrial hygiene (IH), toxicology and environmental consulting company to provide an independent technical review of the existing WRPS IH program, and a critical assessment of the IH Chemical Vapor Technical Basis.

The recommendations in the Critical Assessment of the Technical Basis and Implementation of the WRPS Hanford Site Waste Tank Farm Industrial Hygiene Program report issued by CTEH are being used to help drive improvements in the WRPS IH program, and support the Overarching Recommendation in the TVAR.

In conducting the evaluation, CTEH used a classical industrial hygiene approach to address chemical hazards, which includes:

1. Identifying potential airborne hazards,
2. Conducting a hazard assessment to determine which potential hazards maypresent an actual risk to worker safety and health, and
3. Controlling hazards with the implementation of proper Industrial Hygiene (IH)controls.

The report

In the report, CTEH concluded the technical basis of the WRPS Hanford tank farm industrial hygiene program, as well as its implementation, is sound. CTEH also established WRPS has developed a sound strategy for determining chemicals of primary concern (COPCs) and developing and implementing acute Occupational Exposure Limits (OELs) to guide in-field decision-making. This approach helps to minimize worker exposures that would be of concern for adverse health effects.

CTEH noted WRPS has developed the COPC list as a means of identifying potential chemical hazards. The report also observed WRPS has developed a public database to share analytical sampling data, toxicological data, and ongoing research and testing information.

Additionally, CTEH found WRPS has made a significant investment into direct-reading instrumentation – with detection limits below the site-specific occupational exposure limits. CTEH also noted additional hazard assessment methods in use by WRPS, including both the vapor monitoring and detection system (VMDS) pilot study being conducted in A and AP Farms, and the “RJ Lee” mobile proton-transfer-reaction mass spectrometer (PTR-MS).

The CTEH assessment included an evaluation of the "bolus theory" as described in the 2014 TVAR. CTEH found based on the existing data and standard accepted IH dispersion modeling, the bolus hypothesis is not supported.


Finally, CTEH made several recommendations for improvement to the WRPS industrial hygiene program which include:

  • Development of a comprehensive risk assessment program for both chronic and acute health impacts.
  • Development of a job hazard risk matrix to encompass all job tasks performed throughout the Hanford Site, both tank and non-tank work.
  • Development of a worker education program on odor thresholds, toxicology, and contextual understanding of chemical detections.
  • Development of tank farm specific COPC lists, posting these lists at their respective farms, and ensuring the odors associated with each COPC are cataloged and discussed at pre-job meetings specific to each farm.
  • Provide greater definition of roles and responsibilities within the IH program.
  • Ownership of roles described in WRPS industrial hygiene program documents must be detailed such that the person (or persons) responsible for performing each role is aware of, and held accountable for, the execution of their described duties (as per TFC-PLN-34, Industrial Hygiene Exposure Assessment Strategy).
  • Routinely analyze data collected to inform the comprehensive risk assessment. (At a minimum, on an annual basis.)
  • Ensure direct-reading and analytical sampling methods conform to conventional sampling practices.
  • Provide increased and continual education for the industrial hygiene technicians to provide contextual understanding of industrial hygiene data analysis.
  • Deliver workforce education on the concept of "exposed but protected."
  • Reevaluate the use of self-contained breathing apparatus (SCBA) in tank farms as a minimum level of protection.
  • Evaluation and revision of the current Tank Farm Abnormal Operating Procedure 15 (TF-AOP-15) Response to Reported Odors or Unexpected Changes to Vapor Conditions that would:
    • Reduce the subjectivity of "stronger than normal," or the implication that an odor is abnormal.
    • Increase the speed of reporting of TF-AOP-15 events to the workforce as a means to increase trust and transparency.