If all goes according to plan, it will have been three years since the Washington Monument closed for elevator repairs and the addition of a new security center by the time it reopens to the public. The National Park Service (NPS) announced Monday that the iconic structure at the heart of the National Mall would be publicly accessible again this August, after “possibly contaminated soil in the construction area” was discovered, and now needs to be addressed.

“The modernization of the monument’s elevator is substantially complete, with just final testing and certification of the safety systems remaining,” NPS explained in a release. “The potentially contaminated soil is below the ground surface and poses no risk to public health.” The park service added that the soil was “likely introduced in the 1880s,” when the structure was nearing completion. In more recent years, its elevator system had stalled multiple times.

Maryland-based Grunley Construction Co. has been managing the elevator update and the construction of the permanent visitor screening center—which were originally projected to cost about $3 million and $8 million, respectively. Philanthropist David Rubenstein pitched in $3 million to the project. It was initially expected to be finished by this spring, but for the soil issue. The 555-foot grand monument includes an observation deck at the 500-foot level.