1

To: Susan Fairchild , EPA From: Dave Reeves , RTI

Project Files Date: October 1 5 , 201 4

Re: Wool Fiberglass RTR Ample M argin of S afety

– A nalysis and P roposed C ontrols

I. Introduction

The purpose of this memorandum is to present information used in the ample margin of safety analysis for the U.S. Environmental Protection Agency’s (EPA’s) residual risk review of the national emission standards for hazardous air pollutants (NESHAP) for the Wool Fiberglass Manufacturing Source Category (40 CF R p art 63, subpart NNN) in accordance with section 112(f)(2) of the Clean Air Act (CAA).

Wool fiberglass is produced by melting raw materials (silica sand, soda ash, borite, other minerals, and cullet) in a high temperature furnace and transferring the molt en glass in a thin stream to either a rotary spin (RS) or a flame attenuation (FA) line for fiber formation. If the end product is bonded wool fiberglass, the product must be coated with a binder. Some wool fiberglass facilities that produce bonded wool fi berglass use a phenol

- formaldehyde binder, but the industry has largely phased out the use of such binders in favor of non

- HAP binding agents. Wool fiberglass products are primarily used as thermal and acoustical insulation for buildings, automobiles, airc raft, appliances, ductwork, and pipes. For more information on wool fiberglass manufacturing, see preamble discussion in the November 25, 2011 proposal (76 FR 72776).

S ection 112(f)(2) of the CAA refers to a two

- step process for developing standards to ad dress residual risk. The first step in this process is the determination of acceptable risk. Under th is first step EPA conducted two information collection requests ( ICRs ) that included all wool fiberglass facilities currently operating in the US. The firs t ICR was voluntary and allowed companies to perform HAP emissions test ing on a subset of facility operations, if the facilities were able to demonstrate that the subset was representative of the untested subset. Test results were typically presented as three test runs and provided in units of mass of pollutant per mass of producti on (e.g., lbs of HAP/ton of glass pulled). The ICR responses from all the facilities were compiled in the project database and included information on each facility, process, process equipment, control equipment, costs, and HAP emissions. The second ICR re quested specific information about furnaces and required that all facilities that had not submitted chromium and hexavalent chromium test data conduct and submit Method 29 and Method 061 testing

. The EPA then used a combination of new and existing test da ta to populate the wool fiberglass residual risk modeling file. The risk assessment which evaluated both actual and allowable emissions can be found in the October 2014 Draft Residual Risk Assessment for the Mineral Wool Production and Wool Fiberglass Manu

facturing Source Categories in the Docket. Generally, i f risks are found to exceed 100

- in

- 1 million, we consider this unacceptable and act to reduce risk to acceptable levels by requiring emission reductions of the pollutants responsible for the risk (i.e ., the ‘risk drivers’). If risk is found to be below 100

- in

- 1 million, we consider risk to be acceptable; for the w ool fiberglass manufacturing source category
, risks were found acceptable at 20

- in

- 1 million

. The second step of Section 112(f )(2) provides for an ample margin of safety (AMOS) to protect public health. For the AMOS determination, a search was conducted outside the source category for technolog ies that would reduce chromium emissions

, especially hexavalent chromium

. S imilar process associated with hexavalent chromium emissions with in three industries were found: chromium electroplating, the metallurgical industry and the electric utilit y industry

. The cost s of2

control technolog ies for those industries were evaluated, and two (reducing the operational life cycle for specific process equipment and installation of sodium hydroxide [NaOH] scrubbers) were found
to have reasonable cost effectiveness in terms of dollars per pound of pollutant removed. T he wool fiberglass glass

- meltin g furnace process parameters were compared to those in the chromium electroplating, metallurgical and electric utilit y industries

. These technologies were evaluated, taking into consideration costs, energy, safety and other relevant factors ( such as adverse environmental effect s ) to determine whether risk, although acceptable, could be further reduced to meet a level achieving an AMOS, using the available cost effective emission reduction approaches and that th ese emission reduction approaches are tra nsferable to the furnace operations

. 1

II. Identification of Subpart NNN Risk Driver HAPs and Processes

The November 2011

, February 2013 , and October 2014 draft residual risk assessment s were based on actual emissions currently emitted by industry and are summarized as follows:

2011 proposal risk results  MIR = 40 (formaldehyde*, Cr +6 ) (based on actual emissions) 11,641 people exposed to cancer risk >10

- in

- 1 million 849,000 people exposed to cancer risk >1

- in

- 1 million HI = 0.2 (formaldehy de) HQ = 30 (formaldehyde

– based on REL) Cancer incidence = 0.05 (52% formaldehyde, 47% Cr +6 )

2013 proposal risk results  MIR = 20 (formaldehyde); (based on actual emissions) 1,800 people exposed to cancer risk >10

- in

- 1 million 650,000 peopl e exposed to cancer risk >1

- in

- 1 million HI = 0.2 (formaldehyde) HQ = 30 (formaldehyde

– based on REL) Cancer incidence = 0.04 (64% formaldehyde, 35% Cr +6 )

2014 proposal risk results  MIR = 20 (formaldehyde and Cr +6 ); (based on actual emissions) 6,900 people exposed to cancer risk >10

- in

- 1 million 1,200,000 people exposed to cancer risk >1

- in

- 1 million HI = 0.2 (formaldehyde) HQ = 30 (formaldehyde

– based on REL) Cancer incidence = 0.04 (64% formaldehyde, 35% Cr + 6 )

The EPA also analyzed post

- MACT risks based on the proposed limits in the 2014 supplemental proposal. Below is a summary of the results of the post

- MACT risk assessment and details of the analysis can be found in the October 2014 Draft Residual Risk Assessment for the Mineral Wool Production and Wool Fiberglass Manufacturing Source Categories

.

Post

- MACT estimated risk results  MIR = 5 0 people exposed to cancer risk >10

- in

- 1 million

1 See the following memoranda available in do cket EPA

- HQ

- OAR

- 2010

- 1042 : Control Cost Evaluation for Glass

- Melting Furnaces, Section 112(d)(6) Technology Review for Wool Fiberglass NESHAP, and Development of Background Information on Area Source Emissions Limit

- Determination of GACT for Wool Fiberglass Furnaces at Area Sources ).3 21,000 people exposed to cancer risk >1

- in

- 1 million HI = 0.3 HQ = 7

Risk Uncertainties Although every effort was made to identify all the relevant facilities and emission points, as well as to develop accurate estimates of the annual emission rates for all relevant HAP, the uncertainties in our emission inventory likely dominate the uncertainties in our exposure mod eling estimates. The chronic ambient modeling uncertainties are considered relatively small in comparison, since we are using EPA’s refined local dispersion model with site

- specific parameters and reasonably representative meteorology. If anything, the pop ulation exposure estimates are biased high by not accounting for short

- or long

- term population mobility, and by neglecting processes like deposition, plume depletion, and atmospheric degradation. Additionally, estimates of the maximum individual risk (MIR ) contain uncertainty, because they are derived at census block centroid locations rather than actual residences. This uncertainty is known to create potential underestimates and overestimates of the actual MIR values for individual facilities, but, overal l, it is not thought to have a significant impact on the estimated MIR for a source category.

T he acute screening results were purposely biased high, considering that they depend upon the joint occurrence of independent factors, such as hourly emissions rates, meteorology and human activity patterns. Furthermore, in cases where multiple acute threshold values are considered scientifically acceptable

, we have chosen the most conservative of these threshold values, erring on the side of overestimating poten tial health risks from acute exposures. In the cases where these results indicated the potential for exceeding short

- term health thresholds, we have refined our assessment by developing a better understanding of the geography of the facility relative to po tential exposure locations.

III. Ample Margin of Safety Analysis

The main risk drivers for the wool fiberglass source category were formaldehyde and hexavalent chromium emissions. Formaldehyde emissions are associated with the production of bonded wool f

iberglass products that use phenol

- formaldehyde binders

. Chromium emissions, including hexavalent chromium (Cr +6 )

, are associated with glass

- melting furnaces and the degradation of chromium refractories in the furnace. Most , if not all glass

- melting f urnaces are lined with high

- chrome refractory materials to withstand the extreme temperatures and highly corrosive gases released in the melting process to manufacture wool fiberglass

. Due to th e extreme operating conditions , t he refractories erode over ti me (i.e., 3 to 10 years

– depending on furnace type and design) and are believed to be the source of most of the chromium and Cr +6 emissions . We considered several process alternatives and control options for reducing chromium emissions from glass

- melting furnaces which are summarized in Table 1.4

Table 1. Summary of Options Considered for Wool Fiberglass Ample Margin of Safety Analysis.

Option Feasibility Assumptions Annualized Cost ($M) Total Chromium

Reduction

, lb/yr Replace high

- Cr refractor ies in gas

fired furnaces with

non

- chromium refractories 1 F urnace operating

temperatures and corrosive properties of glass melt composition require highly resistive materials. High potential for industrial accidents. Considered infeasible. $10M per rebuil d every 4 years (versus every 10 years) 2.5M 100%

More frequent furnace rebuilds (every 4 years) Cost prohibitive because of

material and labor

. $10M per rebuild every 4 years (v ersus every 10 years) 2.5 M 464 lb/yr

(for 3 furnaces)

More frequent furnace rebuilds (every ~7 years) Feasible and cost effective

based on net present value approach. $10M per rebuild every 7 y ears (versus every 10
y ea rs) 0.64 M 464 lb/yr

(for 3 furnaces)

Different furnace type s Electric furnaces are less

economical, have less capacity, and require more frequent rebuilds than oxyfuel, but are preferred for production of certain niche markets Electric furnaces could replace oxy

fuel furnaces in capacity. --- 90%

Different furnace designs New designs being

developed/evaluated for large oxy fuel furnaces. -- --- ---

Add

- on controls for furnace exhausts 2 Some Cr emitted as vapor

not in PM; NaOH scrubbers used for chromium

e lectroplating, metallurgical

a pplications, and in the electric utility industry for Cr+6 See Control Cost Evaluation for Glass

- Melting Furnaces memorandum Range

between 212K

- 695K 155 lb Cr/yr ( per

furnace )

Different raw materials

- including cullet Technically feasible, but

reducing recycled glass (cullet)  more costly No test data on contribution of Cr from raw mat erials --- ---

Lower furnace operating temp (to reduce Cr+6 formation) Inf easible . High temperature achieves low viscosity needed for m olten glass to be spun or attenuated. No test data on Cr+6 emissions at lower temps --- ---

1 See reports on New Thermal Shock

- Resistant Dense Zircon and Dense Chromic Ozide Refractories and Bacor High Chromium Refractories available in the docket.

2 See Control Cost Evaluation for Glass

- Melting Furnaces memorandum available in the docket

. Several potential measures or options for reducing formaldehyde emissions from bonded lines were evaluated. First, the EPA reviewed current controls found on bonded lines and found that all were equipped with HAP controls (i.e., incinerator, RTO, or scrub ber) and, as stated in the technology review memo, no new technologies (beyond those already in place) were found. The EPA5

also evaluated the use of non

- HAP binders in the wool fiberglass manufacturing industry to decrease HAP emissions . Recent information from industry stakeholders show that most facilities have phased out the use of formaldehyde on bonded lines, and of the facilities that have not completely phased it out, one or two production lines among several continue to operate using formaldehyde ba sed binders. As a result, the wool fiberglass manufacturing industry has significantly reduced or eliminated formaldehyde emissions.

M ost facilities currently have thermal oxidizers available for use on the bonded lines. Ac cording to their ICR responses, th ose facilities currently not meeting the proposed phenol, formaldehyde and methanol emission limits selectively operate thermal oxidizers (or scrubbers) to meet the existing MACT limits (formaldehyde)

. These types of cont rol are also effective in reducing methanol and phenol emission s

. Therefore, there are no additional capital costs to comply with the proposed formaldehyde/phenol/methanol emission limits and we estimated operation and maintenance (O & M) costs for a the rmal oxidizer at each facility to be $125,000 annually. We identified eight manufacturing lines with emission rates above the proposed emission limits and estimate that approximately 123 tons of organic HAP would be reduced annually at major sources

. Only a small percentage of these forma l dehyde emission reductions are associated with the high(er) risk facilities identified in the draft risk analysis

. However, for three facilities the reductions in formaldehyde emissions ranged from 62 to 77 percent an d resulted in the total facility risk to be less than 1

- in

- 1 million

.

IV. Conclusions

The health risks associated with formaldehyde emissions from wool fiberglass bonded manufacturing lines and Cr +6 emissions from glass

- melting furnaces were reviewed. Both of t hese HAP

- emitting processes were the focus of the ample margin of safety analysis because control measures applied to these processes offer the greatest potential for risk reduction. Industry stakeholders have told us that many facilities are cont inuing to switch their binders and have reduced or eliminated formaldehyde emissions. If formaldehyde and Cr +6 emissions are reduced to comply with the proposed emission limits, then the resulting MIR is reduced to 5

- in

- 1 million. Considering
cost and tech nical feasibility, reducing the operational life of the gas

- fired furnaces from 10 years to 7 years was identified as the most feasible option for increasing the ample margin of safety for wool fiberglass manufacturing facilities.