Slag

FMC, along with others, has been invited by the IDEQ to meet and discuss reconvening the Slag Technical Work Group (TWG) to review the Graded Decision Guidelines (GDGs) which were developed to assess exposure to naturally occurring radiation in elemental phosphorus slag. FMC welcomes this as an opportunity to ensure that the communities of Pocatello and Soda Springs have accurate information about slag.

The TWG was first formed in 1992, based on a recommendation from EPA’s Science Advisory Board (SAB), as the best forum to convene scientist and technical experts to develop the Graded Decision Guidelines through which individual exposure to slag radiation could be interpreted. The program to implement the GDGs (commonly called the “Community Slag Study”) provided individual exposure monitoring, as well as the development of an inventory of slag locations in the community.

As background, phosphate ore was the raw material FMC used to produce elemental phosphorus at the former FMC plant outside Pocatello, Idaho and is currently being used at the P4 Production plant in Soda Springs, Idaho. The ore contained trace amounts of naturally occurring radiation. As a result, slag, a byproduct of phosphorus production, contains low levels of gamma radiation. Commonly known sources of gamma radiation include granite and medical x-rays.

Slag was historically used in the community for road and parking lot construction, construction fill, railroad ballast and in some cases in Soda Springs, home foundations. FMC and Monsanto voluntarily stopped selling slag in 1990, despite repeated requests from users who valued it as a superior source of aggregate. Shortly thereafter, the TWG was formed and the group of technical representatives from the agencies, the community and the companies worked together to develop the Graded Decision Guidelines. The Community Slag Study included an education program and resources were made available (and remain available, funded by the companies) to answer questions about slag and conduct exposure monitoring. The Community Slag Study was largely completed by 2000, and almost 12 years later, FMC agrees with IDEQ that a renewed communication program to ensure that the community has accurate, scientifically-based information about slag is quite appropriate and that all parties take the slag issue very seriously.

The Community Slag Study remains available to all SE Idaho residents and can be accessed through the Southeastern Idaho Public Health District. We would encourage anyone with an interest to contact the SE Idaho Public Health District at (208) 478-6316, or access the following website: www.sdhdidaho.org/comhealth/slag.php.