National Park Service

Old San Juan

The city walls of San Juan, Puerto Rico are a part of the San Juan World Heritage Site. The walls were begun in the 1630s with construction continuing for the next 150 years. They average 42 feet in height and are also about 42 feet thick at their base. The National Park Service began cleaning the walls with D/2 Biological Solution more than 8 years ago.  The current project includes two distinct sections of the wall known as the Santa Elena and the San Augustin. Together they extend 2,600 feet.

D/2 Biological Solution becomes part of a Presidential Executive Order

The National Cemetery Administration now uses D/2.  Quote: "The NCA  entered into an agreement with the National Center for Preservation Technology and  Training, NPS, to evaluate marble cleaners in an effort to minimize damage to historic headstones. The 3-phase study began in 2004 and was completed in 2011. The best  - practice recommendations resulted in NCA's determination to use the preferred cleaner, D/2 Biological Solution…" (Page 3)

From Presidential Executive Order 13287, Preserve America  FY 2011 Triennial Report Department of Veteran Affairs.  

Civil War monuments get D/2 makeover at Chickamauga battlefield.

A six-person preservation team with the National Park Service has been working its way around the Chickamauga and Chattanooga National Military Park giving its Civil War monuments a spring cleaning. The crew, which works out of Frederick, Md., and travels the country to clean monuments, will work at the park for about three months. The group uses the environment friendly cleaner D/2 to clean the structures.