In separate actions contained in one proposal, the EPA is proposing chromium and particulate matter (PM) (for metals) emissions limits for wool fiberglass gas-fired glass-melting furnaces at area sources and major sources as well as residual risk and technology review (RTR) amendments to existing rules for major sources engaged in mineral wool and wool fiberglass production. 

Wool fiberglass products are mostly used for residential insulation; two plants also operate pipe insulation lines.  According to the EPA, there are currently 30 facilities in the wool fiberglass manufacturing source category–10 major sources and 20 area sources.  Products made from mineral wool are generally used in high population density buildings for insulation, fireproofing, and noise attenuation.  The mineral wool air toxics standards currently apply to   7 facilities, all major sources.

Wool fiberglass area sources

Most plants in this sector have become area sources by eliminating or reducing phenol/formaldehyde emissions from the binding process in their manufacturing lines.  According to the EPA, “many” of the remaining 10 major sources have announced plans to become area sources. 

The EPA is proposing a limit of 0.00006 pounds (lb) of chromium compounds per ton of glass pulled (0.06 lb per thousand tons glass).  According to the EPA, most area sources are currently emitting below this level; the Agency has therefore determined that this limit can be achieved by a generally available control technology (GACT).  A PM emissions limit of 0.33 lb per ton of glass pulled has also been proposed.

Wool fiberglass major sources

This action supplements a November 2011 proposal to address the results of a technology and residual risk review the EPA was required to conduct by the CAA for the original 1997 MACT standards for this source category.  After that proposal was issued, the Agency gathered additional information that indicated that gas-fired glass-melting furnaces at wool fiberglass manufacturing facilities exhibit a greater potential to emit chromium compounds and other metal hazardous air pollutants than electric furnaces and also to convert trivalent chromium to more toxic hexavalent chromium. 

Based on that information, the Agency is now proposing limits as follows:

• For furnaces, a PM limit of 0.33 lb/ton and work practice standards for hydrogen fluoride (HF) and hydrogen chloride (HCl).
• For rotary spin lines limits for:
  • Phenol at 0.26 lb/ton (existing) and 0.063 lb/ton (new)
  • Formaldehyde at 0.19 lb/ton (existing) and 0.087 lb/ton (new)
  • Methanol at 0.83 lb/ton (existing) and 0.61 lb/ton (new)
• For flame attenuation lines limits for:
  • Phenol at 1.4 lb/ton (existing) and 0.46 lb/ton (new)
  • Formaldehyde at 5.6 lb/ton (existing) and 3.3 lb/ton (new)
  • Methanol at 0.50 lb/ton (existing) and 0.50 lb/ton (new)

Mineral wool major sources 

This part of the proposal also supplements the November 2011 proposal as follows: 

• Two carbonyl sulfide limits for cupolas depending on whether the cupola is a closed or open-top design;
• HF and HCl limits for cupolas depending on whether the cupola melts slag as an ingredient in its raw material mixture; and
• Revised limits for phenol, formaldehyde, and methanol for the three subcategories of collection/curing lines (horizontal, vertical, and drum),

Start-up, shutdown, malfunction

All proposed limits listed above would apply at all times, including during periods of start-up, shutdown, and malfunction.  Additional requirements have been proposed affecting measurement methods, monitoring, reporting, and recordkeeping.  After a final rule is published, wool fiberglass plants will have 1 year to comply with the limits and mineral wool plants will have 3 years.

EPA’s proposed actions were published in the April 15, 2013, FR.