Frequently Asked Questions Answers: Mosaic Florida Phosphate Mining Manufacturing, Gypsum, Phosphogypsum and gypstack
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Does phosphate mining create radioactive phosphogypsum stacks?

Phosphate mining does not create radiation. Phosphogypsum, a byproduct of the fertilizer manufacturing process, is produced when the phosphate rock we mine is combined with sulfuric acid to form phosphoric acid and phosphogypsum. The phosphogypsum must be filtered and removed so the remaining phosphoric acid can be used to make fertilizer. The phosophogypsum is subsequently deposited on a gypstack under strict standards established by the Florida Department of Environmental Protection (FDEP) and the U.S Environmental Protection Agency (EPA).

Studies show that typical Florida soils naturally contain radiation and this is also true of phosphate rock. Radiation levels are slightly higher in mined lands, compared to levels observed before mining.  Soils found in other parts of the country and world contain higher levels of radiation.

There will be no gypstacks in the counties where we are seeking new mining permits. Learn more about phosphogypsum from the Florida Industrial and Phosphate Research Institute (FIPR) and the International Fertilizer Association (IFA).

Instead of disposing of phosphogypsum in stacks, can’t the material be used for other purposes?

In 1989, EPA regulations required U.S. phosphate companies to store phosogypsum in stacks because of slightly elevated radiation levels in the phosphogypsum. This was modified in 1992 to allow use as a soil amendment for phosphogypsum produced in north Florida.

Trade organizations like the IFA  monitor where and how phosphogypsum is being used internationally.


Under periods of intense rainfall or storms, does the process water from phosphogypsum stacks overflow and impact local waterways?

Managing water in our phosphogypsum stacks is an important part of Mosaic’s manufacturing operations. In 2004, our Riverview gypstack experienced a breach. The incident occurred in a year when an unprecedented four hurricanes struck Florida, leaving the region saturated as a result of extraordinarily high natural water levels and much higher than average rainfall. The water from the breach entered Archie Creek, and subsequently made its way to a small area along the Hillsborough Bay coastline.

This water, which was diluted quickly because of heavy rainfall, also remained very close to shore due to the tropical weather conditions. As a result, it was determined by highly-qualified third party experts that any impacts were temporary and extremely localized.

Following the breach, Mosaic invested approximately $30 million in improvements at the Riverview facility, including infrastructure that allows us to store greater volumes of water and better manage water inventories at the facility. Many of these water management practices have been successfully implemented at other gypstacks in the region.

In addition, Mosaic has performed mitigation activities at the Giant's Camp Wetland Restoration and Oyster Reef Project and partnered on numerous restoration projects in Tampa Bay. In fact, Mosaic’s partnership with the Tampa Bay Estuary Program and implementation of best management practices at its facilities on the Bay have contributed to seagrass populations meeting and exceeding major recovery goals to levels not seen since 1950 and achieving all water quality targets in Tampa Bay for the third year in a row. Read more about the improved health of Tampa Bay.

Isn’t Mosaic simply discarding dirty water into local waterways from mining and manufacturing operations?

No. Phosphate mining and manufacturing operations in Florida are highly regulated. Mosaic complies with regulations put in place by agencies responsible for protecting people and the environment. Water discharging from mining and manufacturing operations is done through permitted discharge points called outfalls. To safeguard the surrounding waterways these outfalls are monitored for water quality parameters.

Today, we monitor 78 active outfalls for water quality and flow based on stringent permit requirements and we analyze surface water for 246 different chemicals. Our record of compliance with these permit requirements is demonstrated in the public record. We follow rigid quality control procedures to ensure that the water released through the outfalls meets or exceeds state water quality standards. Learn more about Mosaic’s water stewardship.

Are Mosaic’s groundwater withdrawal permits higher than are needed for mining and manufacturing processes?

Groundwater withdrawal limits are designed to allow Mosaic’s facilities to operate and continue to produce the fertilizer needed by farmers. In 2012, we worked with water management regulators to design an Integrated Water Use Permit (IWUP), which will reduce Mosaic’s daily permitted groundwater usage by an additional 30 percent over the next 20 years. Today, we recycle or reuse approximately 90 percent of the water at our facilities, and we’re always looking for new ways to conserve water. The IWUP, which included a comprehensive review of Mosaic’s water management practices, was the result of nearly five years of negotiation with the Southwest Florida Water Management District (SWFWMD).

Mosaic previously held seven separate water use permits to run its phosphate mining and fertilizer manufacturing operations in central Florida. By using an “integrated” approach to combine these permits, Mosaic voluntarily reduced its daily permitted groundwater usage by nearly 30 million gallons per day (MGD), a dramatic reduction of 30 percent. Today, our groundwater use constitutes approximately 2 percent of total groundwater use in the SWFWMD.

Mosaic has targeted an additional 10 percent reduction in groundwater use by the year 2020. We’ve identified alternate water supplies like reclaimed water to help us reach our goal. As an example, Mosaic currently uses 5 MGD of reclaimed water in our operations in lieu of groundwater.

Does Mosaic use groundwater before discharging it into the environment?

Responsible stewardship of water resources is a cornerstone of Mosaic’s phosphate operations. We use water in our mining and fertilizer manufacturing operations in a number of ways, to slurry and transport phosphate rock, to protect and hydrate wetlands during mining, to cool process equipment in manufacturing plants and a host of other uses.

Mosaic uses state-of-the-art water treatment methods to meet federal and state standards before releasing water into local waterways through permitted outfalls. The standards are met by blending waters collected from stormwater runoff, non-process water or other sources, like groundwater. We calculate 10 percent of Mosaic's total permitted groundwater use is currently used for blending to meet stringent water quality standards.

Is phosphate mining the largest user of groundwater in central Florida?

No. The total water use in the SWFWMD area in 2011 was 1,022 million gallons per day (MGD). Of that, approximately 2 percent was used for mining operations. This includes water use for phosphate, peat, limestone, sand, shell and gravel mines. Mosaic’s share of the mining and dewatering category is less than 2 percent of the total water use in the region; a relatively small amount considering Mosaic’s water use permits cover a large area in multiple counties as well as several mines and manufacturing facilities.

Will new mining operations impact groundwater use in the region?

No. According to the most recent SWFWMD report, phosphate mining accounts for approximately 2 percent of the total water usage in the District. The phosphate industry Area-wide Environmental Impact Statement (AEIS), an exhaustive study of phosphate mining practices, conducted by the US Army Corps of Engineers (ACOE) and finalized in April 2013, reviewed phosphate water use practices and included the following comments in their final report: “By implementing water conservation practices, including greater reliance on capturing and recycling onsite surface waters for use in the mining and beneficiation activities, groundwater use has been greatly reduced (BBS&J, 2007).” Water conservation was also addressed in Chapter 4 of the AEIS.

Does phosphate mining cause the intermediate aquifer to become polluted or negatively impacted?

There are three aquifer levels: Surficial, Intermediate and Floridan. As a result of mining activities, a temporary drop in surficial water levels may occur. Generally, drinking water is sourced from the Intermediate and Floridan aquifers. However, in accordance with our permits and the strict regulations under which we operate, this change in water level is not allowed to affect areas outside Mosaic’s property line during mining operations. This has been confirmed through years of water quality and water level monitoring. Mosaic’s Integrated Water Use Permit (IWUP) is an unprecedented approach to water conservation and regulation, including the use of Environmental Management Plans (EMPs), a predictive strategy for protecting wetlands up to four years in advance of mining operations. The IWUP goes beyond normal permit requirements and implements more stringent monitoring and reporting requirements, including twice the amount of previous data collection.

Health Impacts

Have there been studies to assess radiation and other potential impacts from phosphate mining in communities where Mosaic operates?

Yes. The Florida Department of Health (FDOH) has monitored radiation levels on pre- and post-mined lands for 30 years. Their monitoring results indicate levels on post-mined lands are within naturally occurring radiation levels in soils.

Since the late 1970s, FIPR has also extensively studied and conducted research concerning radiation, waste disposal, air and water emissions associated with phosphate operations.

Most recently, there have been two independent studies by the FDOH and Hillsborough County Environmental Planning Commission (EPC) on radon emissions that may be associated with the Riverview facility’s phosophogypsum stacks (2010 and 2012-2014). Based on those studies, no elevated radon levels were observed, and FDOH concluded that the monitoring results “are generally low compared to background levels in most of the country.”


Is it true that even after mined land is reclaimed, the mining process causes higher levels of radiation and radon gas, increasing the risk for those who live there?

FDOH has monitored radiation levels on pre- and post-mined lands for nearly 30 years. Their monitoring results indicate levels on post-mined lands are within naturally occurring variations in soils found in Florida.

EPA has found that Floridians are exposed to lower levels of natural background radiation than most Americans and that exposure to man-made radiation sources exceeds the levels caused by natural sources. Man-made sources include cell phones, cell phone towers, electrical power lines, microwave ovens, and medical tests (X-Rays, and CAT scans) among others.

Most homes will be below the EPA action level for radon in air, but a higher percentage may be above the action level when compared to unmined land over phosphate deposits. Radon concentration in a home largely depends on construction practices, and radon is easily and inexpensively mitigated both pre- and post-construction.

Does phosphate mining increase radiation levels on land?

Any time land is disturbed for any purpose, radiation present in the soils may be redistributed and sometimes can be found closer to the surface. The level of radiation in post-mined lands in Florida is still lower than what is observed in some other parts of Florida and throughout much of the United States. Naturally occurring radiation can be found just about everywhere and in everything. All land emits radiation because of the minerals, like naturally occurring uranium present in the soils.

Regulatory Compliance

Is the phosphate industry under-regulated?

Actually, Mosaic is one of the most highly regulated companies in the State of Florida. Florida regulations are among the most rigorous in the nation which is why the U.S. Environmental Protection Agency (EPA) is using Florida’s phosphogypsum regulations as a template for the rest of the nation. Mosaic has developed extensive monitoring systems for air pollution control, surface and groundwater management, employee health and safety, process safety management and waste management/minimization.

Environmental Justice

Are low income and minority residents the victims of pollution from nearby gypstacks?

As part of the Areawide Environmental Impact Statement (AEIS), Environmental Justice concerns as they relate to phosphate mining were specifically addressed. According to the final report, “it is expected that with mitigation, the adverse effects associated with mining would not disproportionately impact the populations of environmental justice concern in the areas leading to a minor degree of adverse effects.”

Mining Moratorium

Should there be a moratorium on mining?

No. A moratorium on mining was considered and rejected by the U.S Army Corps of Engineers as part of their 2013 Final Area-wide Environmental Impact Statement.


What is the impact of phosphate mining to the local economies/communities?

Mosaic brings many benefits to the counties where we operate. In addition to the jobs provided by Mosaic, our operations generate additional revenues for county governments as well as a significant boost to local philanthropic organizations.

Most areas we mine were previously zoned for agricultural use and must be rezoned for mining. As a result of this rezoning, property tax revenue from the land increases by millions, providing benefits to local schools and governments. In addition to property tax revenue, county governments receive a portion of the severance tax paid on each ton of phosphate rock mined at our facilities. With new mining operations, an entirely new revenue stream is created for the county government which can be invested in services for its citizens.

For example, the DeSoto mine plant construction is expected to require a capital investment from Mosaic of nearly $1 billion. This investment creates a ripple effect to surrounding businesses and a further increase in tax revenues for the county government. Construction of the plants will result in the creation of significant temporary construction jobs at the site.

Aside from the company’s cash investments in our operations, we believe that we have a responsibility to support the communities where we operate. After all, this is where we live, work and play as well. Each year, the company contributes millions of dollars to Central Florida charities and the United Way.

During the 2018 calendar year, Mosaic’s economic impact in Florida included:

  • $431 million in payroll
  • $336 million in capital expenditures
  • $34 million in land reclamation
  • $29 million in county tangible and real estate taxes
  • $38 million in state severance and sales taxes
  • $775,000 million to United Way organizations in Florida

Clay Settling Areas

Are clay settling areas (CSA) permitted?

Yes. CSAs are required by the State of Florida to store the liquid clay from the phosphate mining process. The footprint for a proposed CSA is part of the master mining and reclamation plans for each individual mine. Approval is granted by the appropriate regulatory agencies.

Is it true that clay settling areas are full of waste and serve no purpose?

CSAs allow for settling of clay, serve as water reservoirs, and are used for recycling of water and management of stormwater. They also serve a number of useful purposes both during and after mining. For example, reclaimed CSAs are currently being used as pasture land and for farming to grow a number of row crops like zucchini, cabbage and collards. In addition to agriculture, reclaimed CSAs also provide green space for valuable wildlife habitat.

How many clay settling area failures have there been since tougher building standards were put in place almost 40 years ago?

Since 1972, the State of Florida put in place requirements for earthen dams. These included requirements for inspections, maintenance, and certification by professional engineers. This has virtually eliminated dam failures. In fact, there have been only two failures since that time. These incidents were traced to very specific reasons, which led to design modifications and further strengthening of the rules in 1999. There have been no failures or major releases since that time from any dam designed to the upgraded standards. Today, these upgraded standards are considered state-of-the-art and best management practices for earthen dam and reservoir construction. Currently, all Mosaic CSA design specifications meet or exceed Florida regulatory requirements.

Dust at Mining Sites

Does dust at the mining sites contain radioactivity?

Dust is a reflection of the environment in which it originates.  This is true for dust from our mining operations, which may contain low levels of radiation.  The dust generated during the removal of overburden – probably the dustiest part of mining – would be comparable to the dust generated in agricultural tilling or digging in your yard.

The U.S. Army Corps of Engineers (USACE) found during the 2014 Area-wide Environmental Impact Statement process that dust at mining sites remains on the mining sites. This is because the combination of dust particle sizes at phosphate mines and wind speeds result in the dust settling to the ground in less than about 300 feet.


Does Mosaic provide hazardous waste for adding drinking water supplies?

No. The Fluorosilicic acid (FSA) sold by Mosaic is a finished product that has been carefully manufactured, tested, and certified, following the strictest industry and regulatory standards.

FSA meets both customer and regulatory requirements for purity and is not a hazardous waste. FSA has been supplied to municipalities across the country for decades as a safe drinking water additive. In fact, the Centers for Disease Control and Prevention (CDC) named community water fluoridation one of 10 great public health achievements of the 20th century.

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