HEAVY METAL—BANNED


It can take up to 300 hours to prepare and coat the aircraft with primer, he added.


DRIVING THE CHANGE Hexavalent chromium is extremely harm- ful to humans and the environment, which is why AMCOM is prioritizing its removal in its effort to remove heavy metals from the Army’s aviation fleet. It can cause kidney and lung damage, as well as damage to DNA. It can leach into groundwater and cause damage to the ecosystem, Feathers explained.


PRIMED AND READY


Class N primer is applied to a UH-60 by the 1107th Theater Aviation Sustainment Maintenance Group at Springfield, Missouri. (Photo by AMCOM)


an example, alternatives to hexavalent chrome must meet the same standards as their original to be considered. Tey also have to be reviewed by the Army Public Health Center.”


“The [Class N] primer is an epoxy


coating that is applied over the pretreat- ment—which is on the base metal—and is designed to provide corrosion protec- tion and also serve as a base layer to the polyurethane topcoat,” Feathers explained. “Te polyurethane topcoat is a chemi- cal agent-resistant coating and does not contain hexavalent chromium.”


Feathers described these coating layers as similar to the ones you can buy at your local hardware store, but with much higher performance.


104 Army AL&T Magazine Fall 2021


Te Class N primer is applied to every- thing from the aircraft airframe to the components that go on it, like the gear box and transmissions made of magnesium, to all the many small parts on the aircraft. “You name it, just about every part gets primer on it,” Feathers said.


Te primer is applied using high-volume, low-pressure paint sprayers, applied at a specific thickness, and is usually tack free in about five hours and fully cured in 14 days in normal conditions, Feathers said.


But before the new primer can go on, the old coatings have to be removed. “Tere is a cleaning process to remove any contam- inants before a chemical pretreatment coating is applied. Only then can the primer be applied,” he said.


For example, most people know the story of Erin Brockovich’s litigation against Pacific Gas & Electric Co. (PG&E), settled in 1996. Te company had used hexavalent chromium cooling towers to fight corrosion at a Hinkley, California, natural gas compressor station. Te toxic wastewater from the towers was drained into unlined ponds and contaminated the groundwater, affecting an area of about two square miles around the station. “Of course, families in the neighborhood were drinking that stuff and [it caused] a cancer cluster in that area,” Feathers said. PG&E is still working to clean up the site.


Maj. Gen. K. Todd Royar is driving AMCOM’s push to remove current toxic coatings from the fleet and to incorporate new, nontoxic primers into the manufac- turing process. Royar told Quinn that he didn’t just want to meet current require- ments, he wanted to exceed them—to be the leader in safety for aviation.


“So we put together a safety assessment and a risk analysis of all the operations within the Army, in the whole Army. And I was able to break it down to specifically those operations where we had hexavalent chrome exposure. We were able to pres- ent this to the Department of the Army heavy metal working group. As a result of that presentation, we became a member of


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