EPA Questions to Honeywell

on Submitted Exposure Study

EPA Docket: EPA-HQ-OPPT-2008-0918

July 7, 2010

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EPA request for more information on Honeywell Exposure Study

While the general set up of the experiment appears appropriate to test a “Do-It-Yourself” (DIY) 

exposure scenario, the quality of the study characterization is insufficient for EPA to accept the 

conclusion. We recommend that the study be characterized to peer-reviewed journal standards 

and re-submitted.

Specific comments: 

• What chemical was tested? If not the chemical under consideration, please justify why 

the test substance is an appropriate surrogate.

• The study does not appear to be research-grade for the following reasons: 

o Lack of a clearly delineated methodology (no Materials and Methods or sampling 

details)

o What are the technical qualifications of the persons who conducted this testing? 

o The study report mentions a resolution of 0.1% vol, but what kind of analytical 

instrumentation was used and is the physical sampling setup appropriate? 

o What were the temperature and humidity levels during testing? Airborne 

concentrations can vary with changes in these two parameters.

• In addition to the 30 minute TWA, EPA would like to see TWAs for shorter times: 3 

minutes, 5 minutes, and 10 minutes.

o The term "peak" in Table 2 for the 30-min TWA concentrations is misleading, 

because the peak concentrations over the first few minutes could be of concern 

rather than the 30-minute TWAs. 

 Furthermore, the peak concentration and TWA 

values -- currently combined in the Table and Figures of the study -- should instead be 

presented separately. 

o Although all the 30 min. TWAs appear to be “acceptable,” any acute effect could 

require an elevated concentration for as little as 3 minutes. 

o Accordingly, the peak values presented in Table 2 and the Figures may be more 

important than the 30 min TWAs. The Figures show that most of the high 

concentrations occurred in the first two to three minutes. 

• Did Honeywell directly measure the concentrations leaking from the connection to the 

can (can tap), or from the connection to the refrigerant servicing port/service port 

adaptor, in addition to the breathing zone and other area measurements? 

• Did any of the situations simulate a leak from the charge kit hook up or connections, 

similar to that discussed in the Gradient report (p.28)? 

• What size was the garage?

• It appears that your comments are a rebuttal of exposure modeling reported in the SAE 

CRP Final Report. The difference between the box model results and Honeywell's 

measurements, which appears to be several orders of magnitude, is somewhat surprising. 

If appropriate, Honeywell should provide a detailed comparison and contrast of the these 

two studies. 

• On the last page for inhalation exposures, Honeywell says that it supports the EPA 

statement that "EPA has not determined that the manufacturing, processing, and use of 

the substance as described in the PMN may present an unreasonable risk." This is 

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confusing since Honeywell is describing a study involving DIY use of the substance and 

saying that their test MOE's exceed the EPA recommended MOE of 30. 

• Did Honeywell conduct the testing or was it done through an independent third party? 

• Is it Honeywell’s intention to have the cans labeled with information that says that the 

service area must be well-ventilated? 

• Honeywell’s discussion of “worker” (as opposed to DIY consumers) exposures may be 

misleading – workers use different equipment that profoundly changes the exposure 

scenario (except in cases of catastrophic equipment failure or incompetent mechanic 

technique). 

• For additional guidance in relation to your study, see the Advanced Exposure Assessment

section on the webpage "What is OPPT's Approach to Exposure Assessment?" at 

www.epa.gov/oppt/exposure/pubs/opptexpo.htm. 

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