Exposure Assessment Program

People at work

The mission of the Exposure Assessment Program (EXAP) is to provide national and international leadership in the development and use of effective exposure assessment strategies and tools to prevent work-related illness and injury.

Featured Items

NIOSH Manual of Analytical Methods (NMAM) 5th Edition
The NMAM 5th edition website provides the most current methods and guidance chapters and is available worldwide, free of charge.


Exposure Assessment is the multi-disciplinary field that identifies and characterizes workplace exposures, develops estimates of exposure for exposure-response and risk assessment studies, and evaluates the significance of exposures and effectiveness of intervention strategies. Exposure assessment plays a central role in risk management, as depicted in the graphic below.

Flowchart describing the relationship between the concepts of Risk Assessment and Risk Management: 1)Exposure assessment, where the dose-response relationships and associated hazard criteria are identified and defined for the population of potentially exposed individuals; 2) Hazard assessment, where the relevant and reliable exposure and population information is collected for assessment against and refinement of the hazard criteria; 3) Population assessment, where the relevant and reliable susceptibility information for the exposed population is collected for assessment against, and refinement of, the hazard criteria.

Thus, occupational exposure assessment enables effective anticipation, recognition, evaluation, control, and confirmation of protection from workplace hazards. At each stage, health professionals consider the available information and develop a course of action that may include continuing along the original exposure assessment process, determining that no further action is required, performing additional hazard identification, refining the exposure assessment, or improving or adding engineering and/or administrative controls.

Research Priorities

The Exposure Assessment program develops new strategies, tools and methods to measure exposures to a wide variety of chemical, physical, biological, and other hazards present in multiple industries. To do this work, the program intersects with the sector and cross-sector programs within the NIOSH Program Portfolio. Ten sector programs represent industrial sectors, and seven cross-sector programs are organized around safety and health outcomes. The sector programs intersect with the cross-sector programs in a matrix-like fashion, with relevant core and specialty programs playing a supporting role to understand, communicate, and manage risks to worker safety and health. Exposure Assessment is one of numerous core and specialty programs that represent core activities, mandates, special emphasis areas, and methodological approaches.

The matrix approach of the NIOSH Program Portfolio allows multiple programs to work towards accomplishing the shared research goals in the NIOSH Strategic Plan. The Exposure Assessment program contributes to specific goals seeking to understand potentially hazardous exposures or better measure substances known to be harmful. These include goals for research on:


Program Performance One-pager

Program Performance One-Pagers (PPOPs) are a snapshot of NIOSH programs’ priorities, strategies used to make progress towards priorities, recent accomplishments, and upcoming work.

Exposure Assessment Program Performance One-pager

Program Reviews

NIOSH understands that external expert review is one of the most valid and accepted methods of evaluating research programs. In 2017, the Exposure Assessment Program underwent external review by an independent panel of experts. The program was assessed on relevance and impact of its work in the areas of methods development and direct-reading methods and sensors. The program received a score of 8 out of 10 (4 for relevance and 4 for impact). More information, including the evidence package prepared by the program, the report written by the review panel and the program’s response to the panel’s report, are available on the Evaluation of NIOSH Programs page.

To learn more

NIOSH Manual of Analytical Methods (NMAM) 5th Edition

NMAM is a collection of methods for sampling and analysis of contaminants in workplace air, surfaces, and in the blood and urine of workers who are occupationally exposed. These methods have been developed or adapted by NIOSH or its partners and have been evaluated according to established experimental protocols and performance criteria. NMAM methods are used worldwide.

NIOSH Center for Direct Reading and Technologies

Both direct-reading methodologies and sensors are useful to detect and monitor hazardous conditions, to assess and document intervention strategies, and especially to immediately trigger alarms in the event of unsafe conditions.

Health Hazard Evaluations

The Health Hazard Evaluation Program helps employees, unions, and employers learn whether health hazards are present by conducing exposure assessments at their workplace and recommends ways to reduce hazards and prevent work-related illness.


Contact Lauralynn McKernan, Program Manager, at LMcKernan@cdc.gov with any questions.