Limiting Chemical Exposures
JERROLD J. SCHARNINGHAUSEN, Ph.D.
Workplace Safety Division
Directorate of Assessments and Prevention
U.S. Army Combat Readiness Center
Fort Rucker, Alabama
In May 2016, the Environmental Protection Agency (EPA) issued a new drinking water Lifetime Health Advisory (LHA) for two types of fluorinated organic chemicals, perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). The new drinking water LHA is 70 parts per trillion (ppt) for PFOS/PFOA, individually or combined. To put this in context, 1 ppt is equivalent to one drop of water diluted in 20 Olympic-sized swimming pools.
PFOS and PFOA are two types of fluorinated organic chemicals that are part of a larger group of chemicals referred to as perfluoroalkyl substances (PFAS). PFAS are commonly used in household items such as nonstick cookware, clothing, shoes, furniture and carpets. They and are also found in aqueous film-forming foam (AFFF), a firefighting agent used to suppress fuel fires. Animal studies suggest PFAS can cause adverse health outcomes. Scientific evidence to assess health effects of PFAS in humans is currently limited and more research is needed to better understand its association with any disease outcomes in humans. As these chemicals tend to remain in the body for long periods of time, it is recommended that, as a precaution, human exposure to PFAS be minimized.
AFFF is a water-based firefighting foam product used to suppress flammable liquid fires. The Department of Defense began using AFFF as a firefighting agent during the 1970s. Since then, Army fire and emergency service organizations have discharged AFFF in annual and after-maintenance vehicle tests, firefighting training, vehicle operational checks, refractometer checks, and other emergency and non-emergency circumstances. AFFF is considered mission critical because it quickly extinguishes petroleum-based fires.
The Army replaced its supply of long-chain AFFF C8, which contains PFOS and PFOA, with shorter-chain AFFF C6. AFFF C8 refers to the AFFF formulations containing long-chain fluorosurfactants, where long-chain is defined as containing seven or more carbon molecules. Long-chain fluorosurfactants do not break down in the environment, spread rapidly and bioaccumulate (i.e., become concentrated in tissues). AFFF C6 refers to new AFFF formulations containing short-chain fluorosurfactants, where short-chain is defined as six or fewer carbons. AFFF C6 is considered a safer alternative since the short-chain fluorosurfactants leave the body much more quickly. The Army will dispose of existing stockpiles of the AFFF C8 and other AFFF-related waste by incineration.
As a result of the potential health concern, an inventory of potential PFOS/PFOA source areas, such as areas where AFFF were stored or used (e.g., fire training areas, aviation assets, PFOS/PFOA mist suppressant use) was conducted. Water sampling at 2,905 Army locations — including 380 Army drinking water systems, both inside and outside the United States — indicated 13 Army locations with PFOS/PFOA levels above the LHA limit. Where PFOS/ PFOA concentrations were found to exceed the EPA LHA, the Army has implemented appropriate mitigation in accordance with the Comprehensive Environmental Response Compensation and Liability Act. For more information on PFAS mitigation at Army facilities, visit https://denix.osd.mil/Army-PFAS.
PFAS may enter your system through absorption, inhalation or ingestion. Exposure from PFAS through AFFF use will occur primarily during fire suppression or clean-up activities. Workers who may potentially be exposed to PFAS must follow the safe work procedures and recommendations given in the Safety Data Sheets (SDS). When working with PFAS-containing firefighting foams, a minimum level of personal protective equipment (PPE), including rubber gloves, duty wear/overalls, splash-proof goggles and closed footwear, must be worn at all times. If the AFFF is aerosolized, a respirator is recommended. In firefighting situations, a full structural firefighting uniform must also be worn.
Workers undertaking remediation tasks in AFFF-contaminated sites may encounter, in addition to PFAS, other known and unknown hazards at any stage. Therefore, it is important to conduct and review control measures through all stages of assessment, remediation and management. Workers at contaminated sites may need to use a range of PPE according to the type and level of contamination present in addition to those required for handling PFAS. The highest order of control should always be employed. Workers undertaking remediation tasks in PFAS-contaminated sites are also advised not to use groundwater, bore water, surface water or home-grown produce from the area for any purpose. In the event there is an incident involving the use of AFFF, immediately contact your installation spill response team. Their support is critical in order to limit the potential for human exposure and environmental contamination.