Rocky Flats is the name given to the plant North West of Denver in the foothills that made plutonium triggers for nuclear weapons. The plant was in operation from 1952 till 1989 when a combined FBI and EPA raid shut it down. Thru mismanagement and the inherent toxicity of Plutonium this is one of the most toxic sites in America. Building 707 in the middle of the plant had the “Infinity” Room where the needle of the Geiger counter on the higher scale would go to infinity.
The remaining problem is that in the center is still highly contaminated it’s just that it’s 6 feet under the ground - People are not allowed in the center portion and for good reason. Additionally while the surface of the permitted preserve is within safe health limits there was no remediation done to surrounding area which is now the site of thousands of homes especially in the Candellas development directly south. Who knows what was buried just below the surface that was excavated to put in the foundations. My entry point was the south entrance and it is about a block from a massive development.
I recently got a digital Geiger counter as part of a Kickstarter program. I wouldn’t want to walk anywhere on the property without one. Here are my results for the 20 minutes I monitored : average counts per minute or 77. Average microsieverts per hour was 0.07 ,total microsieverts was .03. This translates to about 600 microsieverts per year which is in the safe zone. The upper limit for safety is 1000 microsieverts per year. I guarantee that would not be the case if you were standing in the middle of the property.