Untitled Document
CorrDefense magazine
  Table of Contents Top Stories Featured Projects Inside DoD Conferences Previous Issues Return to CorrDefense web site
Return to CorrDefense web site

Top Stories

Before Exiting, Young Directs Services to Phase Out Hex Chrome

John J. Young, Jr.
John J. Young, Jr.

Before leaving his position as Department of Defense acquisition chief in April 2009, John J. Young, Jr. took an extraordinary step to strengthen DoD policy related to the military’s use of a heavy metal compound known as hexavalent chromium.

Requiring all Services to use substitutes for this material whenever possible, Young directed the Military Departments to further minimize their use of hexavalent chromium salt.

Hexavalent chromium is a carcinogen that is harmful to humans and the environment. However, there are seven variants of the element of chromium. The hard shiny variant of which most people are aware is chromium 0, the metallic form, which was at one time used extensively in making car bumpers. Chromium 0 is also an ingredient used in making stainless steel.

The differences in the seven variants occur in the arrangement of the chromium ions. The variant of chromium, known as chromium 6—which acts very well as a corrosion inhibitor—is also the variant that is harmful to humans and the environment. Hexavalent chromium offers unequaled corrosion protection in unique applications and can be safely used with the necessary containment and personal protection technologies and processes. Once applied, this material remains on a structure and can provide corrosion protection, sometimes for the life of that structure, without subsequent risk to the environment. When proper procedures for handling hexavalent chromium are not used, the material can become a hazard to personal safety and the environment.

In light of hexavalent chromium’s serious safety risks, national and international restrictions and controls on the use of this metallic salt are increasing, Young stated in a memo dated April 8, 2009. The EPA (Environmental Protection Agency) regulates hexavalent chromium emissions under the federal Clean Air Act. Uses of the metal are also monitored by OSHA (Occupational Safety and Health Administration).

“This is an extraordinary situation that requires DoD to go beyond established hazardous materials management processes,” Young wrote, directing the Military Departments to take several actions to “more aggressively mitigate the unique risks to DoD operations posed by hexavalent chromium.”

Providing Corrosion Protection and Flight Safety

“This is an extraordinary situation that requires DoD to go beyond established hazardous materials management processes.”

Hexavalent chromium offers important corrosion prevention and control qualities in organic pre-treatments and primers used to coat a variety of military aircraft. For example, most coatings and primers used on legacy cargo and fighter aircraft such as the Air Force C-130, C-5, and F-16 contain hexavalent chromium, as well as the Navy’s F-18 and F-14. Likewise, coatings and primers used on the Army’s H-60 Black Hawk helicopter also contain hexavalent chromium.

“Young’s memo is a good one because it allows us to use hexavalent chromium when nothing else is available, and it allows us to continue to search for other alternatives,” said Daniel J. Dunmire, Director of the DoD Corrosion Policy and Oversight Office. “This requirement allows the Services to use hexavalent chromium on both legacy and new weapons systems when nothing else is adequate to protect the substrate.”

Some Detailed Requirements in Young’s Directive

In the directive, Young asked the Services to spend money to develop substitutes for hexavalent chromium; fund testing to qualify suitable materials and processes; approve alternative materials that offer equivalent performance in certain applications; and update technical documents and specifications to allow alternatives to hexavalent chromium.

“Young’s memo is a good one because it allows us to use hex chrome when nothing else is available, and it allows us to continue to search for other alternatives.”

In particular, Young’s memo requires the Services to “document the system-specific hexavalent chromium risks and efforts to qualify less toxic alternatives in the Programmatic Environment, Safety, and Occupational Health Evaluation for the system.” These analyses should compare cost and scheduling risks and life-cycle costs for the use of hexavalent chromium compared with specific alternatives.

In addition, Young asked the each of the Military Departments to share their research and development knowledge about suitable alternatives with one another. However, before banning the use of hexavalent chromium, the Program Executive Officers (PEOs) are required to coordinate with their respective Department’s Corrosion Control and Prevention Executive to certify that an acceptable substitute in certain applications is indeed available.

According to the memo, the PEOs and Service corrosion executives are required to consider the cost effectiveness of alternative materials or processes; the feasibility of alternative materials or processes; environmental, safety, and occupational health risks associated with the use of hexavalent chromium or any material substitute in a particular application; the potential for achieving a manufacturing readiness level of at least 8 (eight) for any qualified alternative; the proposed alternatives over the projected life span of the system; and the difference in corrosion performance of alternative materials or processes.

“For such applications where acceptable alternatives to hexavalent chromium do not exist, hexavalent chromium may be used,” Young’s memo states.

A joint effort to understand possible technology alternatives to the use of hexavalent chromium includes the Joint Group on Pollution Prevention, the Military Departments, the Defense Logistics Agency, and NASA. The group will consider gaps in available technology and alternatives with good potential for future use.

Click here to print this article

CorrDefense Home  |  Top Stories  |  Featured Projects   |   Inside DoD |  Conferences  |  Contact Us

© Copyright 2005-2019 CorrDefense