Ambient Air Monitoring Near Mosaic’s Phosphogypsum Stack Here to discuss air monitoring results around the phosphogypsum stack Including dust sampling by EPC and radon monitoring by FDOH Mosaic Fertilizer … US41 in Gibsonton Phosphate rock mixed with sufuric acid = phosphoric acid + phosphogypsum (byproduct) Phosphogypsum slightly radioactive from radium naturally found in phosphate rock EPA – Must be stockpiled

Development of Regional Impact (DRI) DRI is a development having a widespread impact on the community DRI #76 (1984) – Gypstack on east side of US41 DRI #242 (2000) – Expand stack height Condition A.8.a – Conduct dust and radon monitoring Approx. $110,000 provided by Mosaic for studies Dust (2003-07) and radon (2010) studies conducted ... studies showed no significant impacts from stack DRI definition Gypstack on east side began in approx. 1989 DRI #242 included the expansion of the stack height by 50 feet and extend the life of the stack out to 2042 Many citizens had concerns about the expansion (health) Specific condition to require dust and radon monitoring Money used for radon study ($33K) and dust monitoring, including purchase of equip (2 TEOMs-tapered element oscillating monitors) 2003 – 2007 dust sampling at Gibsonton and Progress Village 2010 – 6 month radon study at 3 schools Results presented to the EPC Board in August 2011 Additional monitoring requested by Commissioner Miller … money available

DUST Monitoring Site Map Mosaic Gypsum Stack Closed Cooling Pond Alafia River Mosaic Fertilizer Gardinier Monitoring Site Progress Village Middle School Note landmarks Continued monitoring with another 6 month dust study at Progress Village MS in 2012 Gardinier and Davis Island are continuous monitor sites

Dust Monitoring results Compare Progress Village MS to other locations in County and National Standard Note decrease in the Progress Village bar (green) < 50% of the National Standard Concluded that the schools were very similar to other areas of the County The additional dust monitoring in 2012 showed no notable impact at the school from the gypstack

Riverview Air Monitoring Union Dust Monitoring Dust & Radon Monitoring Radon Monitoring Radon Monitoring Gardiner Dust Monitoring Associated with low-level radioactivity is radon which emanates from the ground Can lead to lung cancer if inhaled in higher quantities FDOH Bureau of Radiation Control - EPC entered into a contract with FDOH in 2012 to do second radon monitoring Nearly identical to initial 6 month study conducted in 2010 Started Nov. 2012 – Completed Jan. 2014 Control site and why it is over 4 miles away Four rounds of monitoring were conducted to encompass both all four seasons 16 sites around the gypstack were selected along with the subject schools (Gibsonton Elementary, Ippolito Elementary, and Progress Village Middle School) and a control site several miles east of the stack Measurements were taken using a Landaurer Alpha Track (tape) and a thermoluminscent dosimeter (TLD) mounted atop a PVC pole 6 feet off the ground and left onsite for 90 days East Bay Dust Monitoring Dust & Radon Monitoring

RADON Monitoring results Radon = quantity of radioactivity, measured in activity (Curie = atoms undergoing transformation) …actual particle Increase at gypstack likely due to addition of data from other seasons … winter = highest Numbers comparatively low No national standard … used EPA action level for INDOOR levels just for comparison CONTROL SITE STILL HIGHER THAN SCHOOLS No elevated levels of concern Note: Small changes from two studies, primarily attributed to additional seasonal influences reflected in second study.

Relative GAMMA Doses From Radiation Sources Gamma = shows exposure by a human body in a given time, secondary decay of radon … longer travel distance, indicative of activity just below the soil in immediate area … energy released Note: Gamma measurements at gypstack and schools decreased an average of 56%

FDOH Bureau of Radiation Control: Conclusions Based on the initial and follow-up studies, the results do not indicate any elevated readings at any of the schools FDOH Bureau of Radiation Control: “None of the measurements taken in this project constituted remedial actions as recommended by various public health agencies. They are generally low compared to background levels in most of the country.” Stack expected to receive material for next approx. 30 years Current Height approx. 240’ Current max height allowed = 260’