View of the Southern Tip of Mare Island Across the Mouth of the Napa River from a Location Near the Site of a Proposed Slag Cement Mill
Not So Harmless After All
We keep hearing reassurances that the granulated blast furnace slag shipped in weekly from Asia for a proposed waterfront cement mill to grind into powder would be harmless.  But repeating something doesn’t make it so.  Neither can a handful of samples typify the chemical makeup of slag in general.  Slag ends up with the impurities present in both the ore deposits fed into the furnace as raw materials and the fuel used to fire the blast furnace, both of which can vary considerably in their chemical composition.  Among those chemicals of particular concern for the sensitive aquatic environment at the mouth of the Napa River is the toxic calcium sulfide found in slag.
Site of Proposed Slag Cement Mill at the Entrance to the Napa River -
Now Hemmed In by South Vallejo Residential Neighborhoods
A patent for the commercial recovery of sulfur from blast furnace slag discusses how the calcium sulfide content of slag can vary significantly in the manufacture of iron from iron ore with coke and limestone:  “Sulfur present in the materials charged to the blast furnace comes out partially in the iron (e.g. 0.03% S), but mostly in the slag (e.g. 1.0% S).  The slag contains the sulfur in the form of calcium sulfide dissolved in calcium aluminosilicate.  Slag formed in a blast furnace using a low sulfur content coke (e.g. 1.0% S) usually contains only about 0.5 to 1.0% S; however, in using a crude petroleum fuel oil which contains 3.0 to 4.0% S in partial replacement of coke in a blast furnace to improve the efficiency of the furnace, the resulting slag has been found to contain usually 50 to 100% more sulfur, i.e. about 1.5 to 2.0%.”  That’s a huge difference just as a result of a minor change in the fuel mixture.
The standardized international risk classification system lists the calcium sulfide contained in blast furnace slag at the highest risk level at R-50: Very toxic to aquatic life.  We're not talking here about degrading the marine environment inside an international industrial seaport complex where only the hardiest worms and molluscs can survive.  The marine waters off the old Sperry Mills site are home to a diverse collection of valuable as well as endangered and threatened fish species.  It sits at the gateway to the Napa River system, essential for the survival of anadromous species like steelhead trout and salmon that must swim past the site to access reproductive territory upriver. 
Anadromous Species Like Steelhead Trout and Salmon Must Migrate Through the Mare Island Strait to Access Headwaters of the Napa River System
The San Pablo Bay is already listed as an impaired water body from legacy pesticides (chlordane, DDT, dieldrin), dioxin and furan compounds, mercury,  polychlorinated biphenyls, selenium, and nickel.  We need to work on cleaning up our old messes, not create new ones.                                             
European slag cement mill
When we view images of the Ecocem ‘green’ slag milling sites in Europe, it looks like they’ve been hit by a blizzard of dirty alkaline slag snow.  After stating the intention to install an updated stormwater system, Appendix J-2 of the Valleo Marine Terminal/Orcem project EIR follows with a less than comforting observation:  “In the event that a storm occurs that is larger than the capacity of the stormwater drainage system, or if flooding occurs during a smaller storm due to debris blockage in the downstream drainage system, flood water would be released overland from the project site and adjacent property and into Mare Island Strait.”
But it’s not only the fishes that would be put in danger.  The neighborhoods and schools of south Vallejo would share the risk right along with the denizens of the Bay and Napa River.  The environmental impact report calls for well over three million gallons of tap water per year just to spray down the roads and offloading equipment in the effort to control dust.  Another 2,400 gallons a day would go to hold down dust released when digging into the huge open storage slag piles.  Even if these best practice dust control measures can be maintained over time, the EIR assumes a percentage would be released at each of the many transfer points. 
The prevailing wind coming across the Bay would pick up some of that fugitive dust and send a plume skyward as it hits the steep slope in back of the site.  That updraft is why you can find parasailing enthusiasts soaring over the bluff above Sandy Beach.  The fugitive dust would settle out in neighborhoods and schoolyards, adding to the high rate of respiratory illness already suffered by south Vallejo residents from living in an industrial corridor.  
Residential Neighborhoods and Schools Have Grown Around the  Sperry Mills Site Now Proposed For a Round the Clock Slag Cement Milling Operation
Some quotes from the current material safety data sheet for granulated blast furnace slag from the US Steel Corporation contradict those repeated claims that this is a harmless material: 
“Granulated Blast Furnace Slag is hazardous according to the criteria specified in European Directives 67/548/EEC and 1999/45/EC and OSHA 29 CFR 1910.1200 Hazard  Communication  Standard.”
“R50 - Very toxic to aquatic life”  “Do not release into sewers or waterways.”
“R36,37,38 - Specific Target Organ Systemic Toxicity (STOST) Following Single Exposure  - May cause respiratory irritation."
“Medical Conditions Aggravated by Long -Term Exposure:  Individuals with chronic respiratory disorders (i.e., asthma, chronic bronchitis, emphysema, etc.) may be adversely affected by any fume or airborne particulate matter exposure.”
Does that sound harmless to anyone?
1857 - The Mare Island  Naval Installation and Town of Vallejo As They Appeared a Dozen Years Before the Establishment of a Flour Milling Facility at an Isolated Site at the Napa River Mouth
(Compare this with the current aerial view at the beginning of the article - things have changed.)
This is no longer the isolated location that existed when a flour mill first established industrial use there in the mid-nineteenth century.  There was no south Vallejo then, and the rail connection laid out in 1869 to run outside of town today cuts through the heart of the City.  Reactivating that rail service would interrupt traffic and emergency service vehicles at nineteen intersections  and subject neighborhoods across town to the noise and attractive nuisance that freight trains offer in urban settings.  Residential neighborhoods with schools and churches long ago filled in around the site.  The remnants of that old industrial infrastructure and legacy zoning do not make it an appropriate place to re-establish polluting heavy industry today.  The highest and best use of the site would fill real community needs for housing, jobs, and sales tax while enhancing a connected waterfront environment from the maritime campus to downtown as envisioned by our current public planning process.
Sperry Landing - A Mixed Use Development Master Plan For The Sperry Mills Site by Golden Associates Included Hundreds of Residential Units with the Waterfront Area Reserved as Park/Open Space. 
The slag cement milling operation is not the first development proposed for this location after General Mills abandoned the site in 2004.  The first set of new owners intended a mixed-use development that would value the waterfront environment as more than just the end of a marine superhighway for slag.  They planned to re-purpose historic structures and help connect the Cal State campus and south Vallejo with the downtown.  The design was completed just before the financial collapse in 2009-2010, and quickly suffered the fate of development projects all across the country. 
The Vallejo Marine Terminal principals managed to purchase the property dirt cheap following a bankruptcy foreclosure.  They convinced a financially strapped City to transfer the leased waterfront portion to them for up to sixty-six years based on the promise to develop an international break-bulk port facility - a purpose which later proved to be out of conformance with the use designated by the regional coastal planning authority.  So here we are today left arguing about slag ships and trains and a cement mill, with more heavy industry projects sure to follow if this one gets the green light. 

The days when polluting heavy industry might be an appropriate use for the south Vallejo waterfront have long passed into history.  That type of development in this location is fundamentally at odds with the pending Bay and River City preferred planning scenario developed with broad public input.  Let's not allow short term financial crises and private sector opportunism to dictate the future character of our community and cripple our public planning process for decades to come.