The ability to calculate a site-specific standard (for any media) is a provision in the Act 2 regulations and is not the only one allowed, but is common practice and one of the three options for standards that can be applied to a site: Statewide Health, Background, or Site-Specific. Other non-residential sites can also calculate a Site Specific Standard if they choose to do so for their Act 2 projects.
This question was also provided to PADEP, to which the following response was provided: “Pennsylvania’s Land Recycling and Environmental Remediation Standards Act (Act 2 of 1995) allows the remediator to select the type of cleanup standard they wish to use for the site. One option is the site-specific standard, and risk assessments are a means available to any remediator to attain that standard. Evergreen chose to use a risk assessment to determine a site-specific standard for direct contact exposures of people with lead in surface soil (upper 2 feet). With this approach they were able to use a more current scientific methodology from U.S. EPA to calculate a risk-based value. Remediators who do not perform a site-specific analysis will generally use the published Statewide health standard default cleanup values, but the site-specific standard option may be used by any remediator and it is not unique to this site.”