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OAR Box 1384 

Prepped by Charmelle Mathews 

Document Number: 

79) ll-E-39 

Docket Number: 

A-94-52 

Printed 7/2/2008 8:42:05 AM Sheet 79 of 264 
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A-94-52 

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\§S>- EPA AIR DOCKET 

MEMORANDUM 

TO: Madeleine Strum 

U.S. EPA/ESD/CCPG 

FROM: Greg LaFlam and Ken Meardon 

Pacific Environmental Services, Inc. (PES) 

DATE: March 29, 1996 

P:\N404 

SUBJECT: Minutes of March 12, 1996 Meeting Between EPA and Representatives of 

the SMC Environmental Subcommittee of the SPI/Composites Institute 

LOCATION: The meeting was held at the U.S. EPA/Mutual Building in Durham, NC, 

11th floor conference room, 9:00 am - 12:00 noon 

ATTENDEES: 

Mr. Perry Bennett 

Mr. Jim Berry 

Mr. Dale Bertelson 

Mr. Jim Bradley 

Mr. Joseph Cech 

Mr. Paul Harper 

Mr. Robert Hoffman 

Mr. Greg LaFlam 

Mr. Ken Meardon 

Mr. Kevin O'Day 

Mr. Erwin Raphael 

Mr. Dave Salman 

Mr. John Schweitzer 

Ms. Madeleine Strum 

MFG 

EPA/ESD 

Cambridge (formerly GenCorp) 

Eagle-Picher Industries 

Menasha Corp. - MPD 

Eagle-Picher Industries 

Interplastic 

PES 

PES 

Goodyear 

Navistar 

EPA/ESD 

SPI/Composites Institute 

EPA/ESD 

(216) 994-5207 

(919) 541-5605 

(317) 392-8081 

(219) 627-2127 

(414) 262-5240 

(513) 629-2418 

(612) 481-6863 

(919) 941-0333 

(919) 941-0333 

(614) 286-7934 

(614) 870-5090 

(919) 541-0859 

(313) 668-4703 

(919) 541-2383 

PURPOSE 

The meeting was requested by the SMC Environmental Subcommittee to discuss the 

preliminary MACT determinations for the manufacturing (compounding) of sheet molding 

compound (SMC) and bulk molding compound (BMC) and for compression molding 

(including injection molding and RTM) mat were developed by EPA and by the Subcommittee. The EPA was also seeking to obtain data and information on the materials and 

processes in these industry subcategories. 
P.3 

Madeleine Strum 

March 29, 1996 

Page 2 i 

DISCUSSION1 

After introductions were made, Mr. Schweitzer stated two goals for the meeting: 

1) to hear EPA's current thinking on MACT for the SMC/BMC compounding and 

compression molding processes, and 2) to make assignments for the group to gather 

additional data and information. 

Ms. Strum began by stating that EPA's compression molding subcategory is 

intended to include not just compression molding with SMC, but all other materials used 

in compression molding. The industry group clarified that the "wet mix" process makes 

use of a compound containing the same ingredients as SMC except for the glass fibers, 

which are used in the form of a "preform" to which the wet mix is added in the mold. 

The industry also clarified the difference between wet mix molding and resin transfer 

molding (RTM). In wet mix molding, the wet paste is applied first and then the mold is 

closed. In RTM, the mold is first closed and then the wet paste is injected. Ms. Strum 

explained that, in EPA's analysis, the BMC compounding subcategory includes only the 

final compounding step itself (in which the glass and filler are added), and not the 

preliminary paste mixing process (if performed). This latter process is considered to be 

similar to the resin mixing that is performed within many of the other subcategories of this 

industry. The EPA stated that it is presently contemplating that resin mixing from all 

subcategories be treated together, and be subject to certain equipment standards and work 

practices. J 

MACT Floors 

Ms. Strum began a discussion of EPA's preliminary MACT floor determinations 

for resin mixing (which includes paste mixing for SMC and BMC in addition to other 

processes), SNIC compounding, BMC compounding, and compression molding (SMC, 

BMC, and wet mix). She stressed that MACT floors need not be in the form of numerical 

emission limitations. 

General/resin mixing 

The MACT floor consists of work practices as currently performed by the average 

of the top performing 12 percent of facilities. Containers (such as buckets, totes, barrels, 

etc.) with volatilizing HAP materials would need to remain covered except when material 

was being added to or removed from the container. One group member said that, at his 

company, nylon film is placed over the resin mix tank as it is moved around the plant. 

This provision of keeping all HAP-containing vessels covered would be applied to HAPcontaining vessels in all process subcategories. 

_ ~ _ 
P.4 

Madeleine Strum 

March 29, 1996 

Page 3 ! 

A second part of the floor consists of mixers that are kept covered during the 

mixing process and at all times when it is not necessary to open the mixer to add or 

remove material. Ms. Strum suggested that this provision might take the form of a "no 

visible gaps" requirement. Company representatives said that these mixers are typically in 

the form of large barrel-like tanks, approximately 4 to 5 feet in diameter. They felt that 

minor gaps are typically necessary and should be allowed, such as for the agitator shaft 

passing through the cover. Group members referred to sealing approaches that have been 

tried, such as adding a teflon or rubber washer/grommet to the shaft to help seal the 

opening. The group emphasized that materials need to be added during the mixing 

process; the agitator and lid are typically raised to allow for the addition of filler material 

out of 50-60 lb bags. It was pointed out that dust is generated during the addition of filler 

and, as a result, baghouses are typically in place to remove dust away from the operator. 

Other differences noted by group members included the use of stationary tanks where the 

agitator is moved from one tank to another (e.g., by overhead hydraulic lift), versus 

portable tanks that are moved to fixed mixers. One group member noted that the mixer is 

typically "off center" to provide vortex mixing. 

One member (Navistar) suggested the possibility of a minimum headspace standard 

for mixers, possibly combined with a maximum percent open area requirement. Mr. 

Berry cited the refrigerated headspace requirement in the solvent metal cleaning standard 

as an example. Mr. Schweitzer stated that covers have been shown to have little impact 

on reducing emissions (as long as there is sufficient headspace in the mixer). He said that 

he would provide an engineering analysis that shows this, as well as descriptions and costs 

of the types of mixers in use. 

SMC compounding 

Ms. Strum stated that EPA agrees with the SPI on the MACT floor for SMC 

compounding at existing facilities, which is reflected by work practices consisting of nylon 

film (rather than polyethylene) and folding the edges to seal the sheet. Group members 

offered to obtain price data for the two types of film material. 

With regard to new sources, Ms. Strum stated that, since one source (Navistar) 

uses an incinerator to control its SMC machine emissions, the floor for new sources 

consists of that level of control (currently estimated at 90 percent overall control efficiency). Industry claimed that Navistar would not be using this control if not for its painting 

operations, j Navistar indicated that due to State lawtf;had to control the SMC machine or 

reduce its emissions from the process unit. They considered buying a new machine as that 

would divide the emissions between two machines (which would meet the Ohio requirement), but made the decision to vent the SMC emissions to the existing incinerator. Mr. 

Schweitzer and several group members expressed disagreement with EPA's using a 

combination painting/SMC facility to represent MACT for all new SMC operations. 

3 
P.5 

Madeleine Strum 

March 29, 1996 

Page 4 

Ms. Strum asked if the group has any emissions data from SMC compounding. Mr. 

Schweitzer said that they could provide such data. He pointed out that emissions are very 

low (about 10 lb/hr), and could be reduced to around 5 lb/hr if covered doctor boxes and 

reduced air flow are implemented, based on tests of pultrusion operations. Group 

members also emphasized that incinerators would create their own emissions of CO and 

nitrogen oxides (NOJ. Ms. Strum stated that the newer incinerators produce very niinimal 

NOx emissions. Mr. Schweitzer said that the flows from SMC machines would be in the 

range of 100 to 400 cfm, with a styrene concentration of no more than 400 ppm, so use of 

a control device may not be practical. 

Ms. Strum asked the group why closed doctor boxes and reduced air flows should 

not be part of MACT for existing facilities. Mr. Schweitzer responded by noting that 

these techniques are based on a pultrusion study and there are no data for SMC compounding specifically. Group members indicated that every company represented at the meeting 

is using nylon co-extrusion as its SMC film. 

On the subject of using condensers instead of incinerators for controlling emissions 

from this application, group members said that styrene polymerizes and is difficult to 

control in this type of control system. Mr. Schweitzer stated that cryogenic condenser 

temperatures would be necessary, and these cannot be feasibly attained at typical SMC 

facilities. Also, the collected styrene would contain impurities, making reuse of the 

recovered styrene impracticable. As a result, this approach would "kill" the economy, 

creating a hazardous waste stream and offering no opportunity for recycling or reuse. 

BMC compounding 

The MACT floor for existing sources consists of work practices, such as covered/ 

enclosed containers and BMC mixers (compounders). For new sources, the MACT floor 

reflects the control achieved by the incinerator being used at one facility (Fibercast), 

estimated at the meeting at 49 percent overall system control efficiency. (A discussion 

with this facility after the meeting showed that the overall efficiency for this controlled 

operation is 95 percent.) Mr. Schweitzer asked why a covered compounder would need to 

be further controlled with a control device. He suggested that a closed BMC compounder 

may be equivalent in the level of control to a compounder controlled using a control 

device. He stated that the control system at Fibercast is primarily oriented toward 

controlling the centrifugal casting operations, which is a high emitting process, and that 90 

percent of the operation is centrifugal casting and 10 percent is BMC compounding. 

Further, it was felt that BMC mixers have no vents, but that emissions are released 

through the door when it is opened to pump paste into the mixer and the air inside is 

displaced. The EPA and PES said they would contact Fibercast to determine how the 

compounding operation is controlled (mixer exhaust, room exhaust, etc.). 

1 
P.6 

Madeleine Strum 

March 29, 1996 

Page 5 

Compression/injection molding/RTM 

For compression molding, the MACT floors were not set on the basis of BMC/ 

SMC/wet mix styrene content because styrene was not considered to be the driving force 

in emissions from the molding process. Both existing and new source MACT floors 

consist of work practices, primarily maintaining covers on all HAP-containing vessels 

except when removal of the cover is necessary to add or remove material. 

Another potential measure involves the number of SMC or BMC charges that are 

"pre-cut" or removed from the sealed source of bulk material prior to the actual molding 

step, and the covering of such charges until they are actually used. The EPA felt that 

some limit on pre-cutting (and pre-stripping of SMC) may be an effective measure. Group 

members were in agreement on the covering of charges, saying that the industry already 

covers pre-cut charges (using plastic film with the edges tucked under) as a quality control 

step to prevent degradation of the material. However, the industry was concerned about 

limiting the number of "pre-cuts," stating that they often prefer to cut a certain number of 

charges ahead, so that production is not interrupted when the operator is called to perform 

other tasks. Also, multiple mold cavities may be used for simultaneous molding, which 

necessitates that the correct number of charges be prepared in advance of molding. The 

conclusion reached was that only those charges "in use" should be pre-cut (which may 

translate into one molding cycle). However, the most reasonable statement of this 

requirement still remains to be worked out. 

The MACT floors for injection molding processes using thermosets consist of the 

same work practices that are applicable to compression molding. One company (Goodyear) performs injection molding by slitting SMC into certain widths, which are rolled into 

bundles that are men covered with nylon. The bundle is placed into a hopper, pushed into 

a stuffer, and then into a barrel from which it is hydraulically injected into a mold. The 

charge is about 20 lbs and 1 square foot, and 5 inches deep. The hopper is a little bigger 

than the charge. Another company (MFG) stated that their process is very similar. At 

Goodyear, styrene (approximately 1 cupful) is manually poured into the hopper to allow 

the tacky material to be fed in smoothly. This company claimed that styrene is the only 

material that will work in diis application. MFG did not know if styrene was used for this 

operation at its facility. 

Cleaners 

The group members were asked about the cleaners used in their operations. Most 

of the participknts have eliminated the use of methylene chloride (MCI). One company 

(MFG) stated that, due to frequent changes of its pigmented resins used to make small 

batches, the lines have to be torn down frequently so that they can be cleaned thoroughly. 

The company stated that the only effective cleaner for this job is MCI. Therefore, while 

^ 
P.7 

Madeleine Stnim 

March 29, 1996 

Page 6 

they have dramatically reduced their MCI use, they have not been able to totally eliminate 

it. This member pointed out that use of pigmented resin mixes eliminates the need to paint 

the parts, which saves a great quantity of VOC/HAP emissions. Another company (EaglePicher), which has less need for frequent color changes, offered to share its non-MCl 

cleaning methods with the other companies (possibly through a visit to its facility). One of 

the company's methods for cleaning involves hot water jets. Group members were 

generally not willing to concede that all methylene chloride could be eliminated at all 

facilities. Mr. Schweitzer offered to survey several companies in these subcategories on 

their use of cleaners and report back to EPA by March 31, 1996. 

Additional HAP cleaners in use include a xylene solution (mold cleaning) and the 

styrene monomer itself. The styrene used for cleaning is often reused in the process by 

adding it to the resin matrix. The discussion then focused on the possibility of allowing 

the use of the monomer for cleaning, so long as it was reused in the process. However, 

Mr. Schweitzer pointed out that overall emissions may not be reduced by reusing the 

styrene cleaner. He said that, a few years ago, a proposal to reduce HAP cleaner use by 

custom molders was prepared, and he would try to locate and supply this proposal to EPA. 

Scrap 

Ms. Strum asked whether the industry keeps records of scrap as a method for 

evaluating the efficiency of the process. Group members indicated they track four 

categories of scrap: 1) raw material (resin, paste, etc.) never formed into finished 

compound, 2) trim scrap (excess/edges of charge material), 3) production rejects, and 4) 

QC (test) scrap from machine setup, etc. Companies attempt to minimize waste, and use 

records of scrap to correct operator or production problems, but these records are not used 

to evaluate process efficiency. The companies collect daily records, and prepare monthly 

summaries. 

General 

The industry members asked about EPA's current schedule. Ms. Strum cited April 

1997 for proposal, and April 1998 for promulgation of this NESHAP. A framework for 

the proposal is iexpected in June 1996. 

Ms. Strum mentioned that EPA is considering performing testing at either a 

pultrusion or an SMC production process. Since the SMC machine at Navistar has an 

existing total enclosure, this location was under consideration. The Navistar company 

representative was not able to make any commitment, but offered to investigate the 

feasibility of such a test taking place at their facility. 

•£ 
P.8 

Madeleine Strum 

March 29, 1996 

Page 7 

Action Items 

Mr. Schweitzer (representing the group's combined efforts) agreed to research and 

obtain information, and supply EPA with data to assist in the development of the regulatory proposal. These action items are: 

1. Develop a survey of cleaner use (especially HAP cleaners) by custom molders, 

send to several companies on March 14, and report the results to EPA by March 

31, 1996. 

2. Locate and provide to EPA the previous industry proposal to reduce the use of 

HAP-containing cleaners by custom molders. 

3. Research and provide to EPA descriptions of resin mixers. 

4. Provide to EPA data indicating the relative emissions for open and covered mixers. 

5. Obtain pricing information for the two types (nylon and polyethylene) of SMC film 

material. 

6. Provide to EPA data on emission levels from the SMC compounding process. 

7. Provide to EPA definitions of the processes discussed at the meeting so as to 

include all of the variations. 

In addition, the representative from Navistar offered to look into the possibility of 

making the company's enclosed/controlled SMC machine available for emission testing by 

EPA. 

The EPA and PES said that they would investigate the control system in use for the 

BMC compounding operation at the Fibercast facility in Sand Springs (Tulsa), Oklahoma. 

7