To: Project Files From: Susan Fairchild

Project Docket (EPA-HQ-OAR-2010-1041) Date: May 1, 2012

Re: Mineral Wool Industry Telephone conference calls on May 1, 2012

Two phone calls were made by the project lead to industry representatives that had stated in the April 

30, 2012 EPA/Industry meeting they would provide EPA with additional information on which to 

consider HF, HCl and COS limits for the final rule.

Steve Edris , Thermafiber 

There are 2 types of cupolas- closed top and open top. When a cupola is closed top its air flow is 

restricted and controlled through ‘tweers’, which are small ports in the bottom of the cupola through 

which air is drawn at a specific rate. Closed top cupolas have a different emissions profile as a result of 

being closed and having a controlled air flow.

Open top cupolas are open to the air and air flows unrestricted and uncontrolled through the cupola. 

The air flow rate is not regulated and so the emissions profile through an open top cupola is different.

All mineral wool products can be made on either open or closed top cupolas. 

We put sorbent injection in before the baghouse to reduce SO2 and we expected this would be able to 

get any HF or HCl that was emitted, but it doesn’t achieve the level of control that would be required by 

the proposed limits. So it seems like the best control can’t achieve your proposed limits, and these 

pollutants are not a real health threat anyway at these concentrations, so why is EPA pursuing such tight 

limits for these pollutants?

Translating the costs we’ve incurred to achieve control across the industry is not really appropriate in 

this situation because we are not spending this money out of our profits- we actually declared 

bankruptcy years ago and went through a restructuring. We are owned by a trust and our profits go to 

benefit asbestos victims that were former employees of the company. We can’t really go out of business 

as a result of costs, we just don’t make as much money for the trust. So the rationale that one company 

spent all this money and the others can too isn’t really appropriate for this industry.

Chris Bullock - IIG

Coke used at all mineral wool facilities is ‘foundry’ coke- scraps from GM and other foundries. The other 

coke available in the US is furnace coke. Furnace coke is higher in volatile content but it won’t melt 

rock. Furnace coke cannot be used to make mineral wool. The cost of foundry coke is 5X what it cost in 

2003. 

Slag used in IIG mineral wool production is iron ore slag- it is about 40% Si, 10-12% Al, 10% MgO, 30% 

Ca, some FeO and trace amounts of other metals. This is slag made from the first melt (primary iron) of 
the iron ore. Some slag used at other mineral wool producers is EAF slag which has different chemistry 

because it is collected from recycling scrap iron, which has already been melted at least once. So the 

slag is much lower in iron and other metals. Different chemistry of the slag will make mineral wool 

products for different uses. One does not necessarily substitute for another because each must meet 

the specificity of its’ end use, and meet UL specifications for what those end use requirements are. So 

although each cupola could theoretically produce any mineral wool product, the fact is that the product 

is a result of the raw materials available to the mineral wool producer’s location. None of our 

companies would transport slag from across the country. We all use the rock or slag that is close to us. 

If a slag producer (for instance, the iron ore plant from which we get our slag) were to close down, we’d 

be in a difficult position because we’d have to make product to fill either a new niche or make the 

product fill the existing niche with a different (i.e, mostly rock?) chemistry. 

We have invested in lots of controls to reduce our air pollution and it’s not really okay with us to give 

the rest of the industry a pass. The incinerator for our 2 cupolas cost us $5.5M; the new electric furnace 

was $6M and $1M was spent on restructuring the plant.