# EPA Questions to Honeywell on Submitted Exposure Study

EPA Docket: EPA

- HQ

- OPPT

- 2008

- 0918

July 7, 2010

### EPA request for more information on Honeywell Exposure Study

While the general set up of the experiment appears appropriate to te st 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 min utes, 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.

**•** D id Honeywell directly measure the concentrati ons 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 ki t 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 resu lts 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, Ho neywell 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 isconfusing 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 informat ion 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.