Health Hazard Assessment (HHA)

 Hazard Category - Chemical Substances

Last Updated: July 19, 2021
Skip Navigation LinksDCPH-A Home / Topics / Workplace Safety & Health / Health Hazard Assessment (HHA) / Hazard Category - Chemical Substances

Chemical Substances

Coordinate with the Health Hazard Assessment (HHA) Program early in the acquisition process in order to eliminate or control potential exposure to chemical substances. Multiple subject matter experts across APHC (such as the Industrial Hygiene Field Services Division and Toxicity Evaluation Division) provide input for HHAs related to chemical substances.

Soldiers exposed to chemical substances can suffer a variety of health effects based upon many factors including the chemical properties, concentration, route of entry, use scenario, exposure duration and frequency, and individual susceptibility. Exposure to chemical substances may elicit an immediate or acute response to a high-intensity exposure, or result in a delayed response to a low-level chronic exposure. Simultaneous exposures to multiple chemical substances may lead to additive or synergistic effects, particularly when different chemicals produce toxic effects in the same target organs of the body.

Sources of potentially hazardous chemical substance exposure may include, but are not limited to, any system that produces combustion products (e.g., weapon systems, vehicle engines, generators, cooking burners) or requires routine, prolonged exposure to toxic materials. Combustion products are a complex mixture of hazardous chemical substances. Nearly all weapon systems produce combustion products that may be considered potential health hazards.

Data Requirements

Provide a detailed use scenario including information such as the exposure duration and frequency (e.g., number of rounds fired, hours spent inside a shelter), required tasks of system operators, operational environment, and expected concentrations of chemicals (e.g., munition composition). Collect toxic hazard test data IAW TOP 02-2-614A and TOP 02-2-622 for military vehicles and military equipment and materiel, respectively.1,2 Test conditions should be representative of the system's use scenario. Provide the safety data sheet (SDS), composition, purpose, and quantity of any miscellaneous chemicals used in the operation and maintenance of the materiel. 

Health Protection Criteria

An HHA applies the Occupational Safety and Health Administration (OSHA) Permissible Exposure Limits (PELs) to chemical substance exposures, or the American Conference of Governmental Industrial Hygienists (ACGIH®) Threshold Limit Values (TLVs®) when they are more stringent than the PELs.3,4 Military-unique standards may be applied to some military-unique exposures (e.g., carboxyhemoglobin limit for carbon monoxide exposure5). 

Toxicity Clearances and Assessments

The APHC Toxicity Directorate performs toxicity clearances (TCs) and toxicity assessments (TAs) of materials (e.g., fabric treatments, solvents, cleaners, corrosion inhibitors) prior to their introduction into the Army supply system to ensure the safety of Army personnel.6,7 The materiel developer is responsible for identifying new materials within their program and requesting a TC or TA. The HHA Division may assist in identifying new materials. TCs or TAs may be requested by email ( using the formal, signed memorandum template and information here.

Other Considerations

Batteriesfire extinguishing agents, and refrigerants are not within the scope of the HHA Program because they do not present a health hazard during normal use. 

Routine exposures to fuels and non-fuel petroleum products, oil, lubricants, and coolants are typically not assessed in an HHA because they are widely used in nearly every Army system. Operational exposures are expected to be limited to dermal or inhalation exposures during refueling and occasional maintenance. Personnel serving in a specific military occupational specialty (e.g., 92F) are trained in handling these compounds. 


(1) ATEC. 2020. Test Operations Procedure (TOP) 02-2-614A, Toxic Hazards Testing for Military Vehicles. External Link

(2) ATEC. 2020. TOP 02-2-622, Toxic Hazards Testing for Military Equipment and Materiel. External Link

(3) Code of Federal Regulations. 2016. Title 29, Part 1910.1000, Air Contaminants. External Link

(4) ACGIH. 2021. Threshold Limit Values (TLVs®) for Chemical Substances and Physical Agents and Biological Exposure Indices (BEIs®). Cincinnati, OH. External Link

(5) DOD. 2020. MIL-STD-1472H, Department of Defense Design Criteria Standard: Human Engineering. External Link

(6) DA. 2020. Regulation 40-5, Preventive Medicine. External Link

(7) DA. 2017. Regulation 70-1, Army Acquisition Policy. External Link