1 Pennington-Lawrenceville Rd., Pennington NJ 08534 ♦ afinkel@law.upenn.edu 

Mr. John Schaefer 

U.S. EPA, Office of Air Quality Planning and Standards 

Sector Policies and Programs Division 

VIA E-MAIL 

 

Re: Docket ID No. EPA-HQ-OAR-2014-0471 

May 19, 2015 

Dear Mr. Schaefer: 

 The comments on the proposed listing of 1-bromopropane (1-BP) as a Hazardous 

Air Pollutant (HAP) by Albemarle Corp. (and their consultants) and by Enviro Tech 

International are replete with legal, scientific, and policy misstatements. I trust that EPA 

will not deny the HSIA and NYSDEC petitions based on misinformation and faulty logic, but 

in the interests of clarity, I will briefly enumerate my concerns in each of these areas. 

Legal Standard: 

All of the speculation contained in the recent comments about the exact 

magnitude of the individual risks to those exposed to 1-BP is only relevant upon a 

dubious interpretation of 42 USC §7412. Mr. Nestrud’s comments on behalf of 

Albemarle (p. 2) cite a personal communication with you (“John Shaefer” [sic]) as the 

source of the purported “requirement” that EPA conduct the same full quantitative risk 

assessment under 7412(b)(3) that it would conduct under 7412(f) when it sets a NESHAP. 

I assume you made no such claim, as that would contradict a plain reading of the Clean Air 

Act Amendments of 1990, and would confuse the well-understood distinction (dating back 

at least as far as the 1983 NAS “Red Book”) between hazard identification and risk 

characterization. Section 7412(b)(3)(B) is quite clear: EPA must grant a petition to list a 

substance as a HAP if “emissions... of the substance are known to cause or may reasonably 

be anticipated to cause adverse effects to human health.” Section (b)(2) above is even 

more clear that listing is a hazard-identification activity—here the Agency shall (emphasis 
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added) add a substance to the list if it “may present a threat of adverse human health 

effects,” with no mention of emissions. 

 I will not belabor here whether it is possible that a reviewing court would interpret 

“emissions” in (b)(3)(B) to mean “the substance must currently be emitted in quantities 

large enough that exposures somewhere in the U.S. are above a biological threshold.” I 

think that is a much more tortured reading that this plain-English reading: “the substance, 

if emitted, is capable of causing adverse health effects.” Hopefully we will not have to hash 

this out in front of a judge (presumably one who knows well the recent Supreme Court 

cases confirming that EPA can, and sometimes must, not consider certain criteria when it 

makes findings, factors that it may or must consider later when it sets regulatory limits). 

But even if (b)(3)(B), in contrast to (b)(2), requires EPA to consider emissions when listing, 

there is no evidence whatsoever in the record here that 1-BP can present itself in 

concentrations too small to cause (or reasonably be anticipated to cause) cancer and 

neurological impairment (see below). Instead, the commenters have filled the record with 

risk estimates, but there is no mention of “it can cause adverse effects, but too few of them 

to matter” anywhere in 112(b). And even if the commenters had offered any evidence that 

1-BP has a threshold below which no harm at all can occur, the burden would be on them 

to provide convincing evidence of this. EPA itself wrote in 2003 (68 Federal Register at 

65651) that “Uncertainties concerning the risks of adverse health or environmental effects 

may be mitigated if we can determine that projected exposures are sufficiently low in 

relation to levels where adverse effects may occur to provide reasonable assurance that 

such adverse effects will not occur” (emphasis added). The commenters cannot possibly 

provide such assurance; all they have tried to do (quite unconvincingly, in my expert 

opinion as a risk assessor) is to suggest that these effects will occur too infrequently for the 

substance to be listed, and EPA is not permitted to accept such an irrelevant judgment even 

if it found the supporting arguments convincing. 

 I hope you will pardon this analogy, but the Amtrak derailment of the other day is 

fresh in my mind as I live near Philadelphia: if DOT was deliberating whether to “list” the 

Port Richmond curve as being dangerous enough to merit a warning sign, imagine if 

someone objected to a sign on the grounds that “hardly any trains go by there anyway, and 

they have a lot of empty seats on them.” Hazard is hazard, and risk is risk: the hypothetical 

“listing decision” for the curve would be based on a determination that the curve was 

capable of causing a derailment, not on the frequency at which derailments might occur. 

Besides, I hope it is obvious to EPA (see below) that emissions are almost wholly within the 

control of the very commenters who seek to dissuade you from listing! Their arguments 

amount to “we promise not to sell enough of this stuff to cause a big problem,” and I 

strongly caution against EPA accepting such an implicit promise. How little or how much 

they sell (and others emit) affects the risk of 1-BP; the hazard of 1-BP is your concern in 
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this proceeding, and EPA cannot legally deny this petition on the grounds that the risk 

might remain low, if the manufacturers respond to a ruling in their favor by selling less and 

less of a product now (incorrectly) not deemed to be hazardous. The time to consider the 

quantitative “significance” of any risks is when the Agency is contemplating actually 

regulating the hazard, not when it is deciding whether the hazard exists1. 

Scientific Claims: 

 

Gradient Corp.’s risk assessment amounts to selective “manufactured doubt.” I have 

no objection to a commenter demonstrating that uncertainty in risk has been understated 

(it almost always is), other than to repeat my concern here that EPA should ignore claims 

that 1-BP is not a HAP because it’s not “risky enough” by someone’s judgment. But surely 

the uncertainty in 1-BP’s risk extends above as well as below the point estimate proffered 

by the petitioners; Gradient seems to have no interest in that portion of the uncertainty 

distribution. Perhaps there should indeed (as Gradient argues) be a slight downward 

adjustment of the IUR to account for interspecies differences in dosimetry; perhaps also 

there should be a slight downward adjustment to gamble on the possibility that by chance 

there were not “enough” tumors in the control animals compared to previous experiments 

on the same strain of mouse. But what about the failure to assess cumulative and aggregate 

risk, which would suggest looking at the total number of tumor-bearing animals in both the 

control and exposed groups? What about the recommendation of the National Academy of 

Sciences Science and Decisions report, which urged EPA to adjust its animal-based cancer 

potency estimates upwards by a factor of from 10- to 50-fold to account for the known 

interindividual variability in susceptibility to cancer in the outbred human population? 

Like the cherry-picking in the Gradient report, these objections to the point estimate are 

reasonable in light of uncertainty, but are one-sided. Again, I urge EPA to follow the statute 

and assess the hazard of 1-BP in this proceeding, but if it is going to incorrectly consider 

quantitative risk estimates, it must consider estimates both below and above the point 

estimates the petitioners offered. 

Secondly, as a former senior executive at OSHA I find the recent comments offensive 

in their willful ignoring of worker exposures and risks. As I demonstrated in my 

unrebutted comments submitted to the record two months before the (revised) end of the 

comment period, the best estimates of current occupational exposure to 1-BP center at 

roughly 60 parts per million (300 mg/m3)—therefore, trying to “prove” that 

concentrations U.S. citizens are exposed to tend to fall below about 1 part per billion (the 

 

1 As an expert in the litigation to which Mr. Morford refers on p. 7 of his (unnumbered) letter to the docket, I 

am privy to information contradicting several of his statements about that case, but I will not document those 

misstatements in this public document. 
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concentration needed to make the risk fall below 10-6) is completely oblivious to the real 

risks posed by 1-BP. 

Third, Gradient’s comments (pp. 5-8) about the possible nonlinearity, threshold, or 

species-specific mode of action for 1-BP are wildly speculative and incomplete. Their own 

conclusory statement on p. 6 says it all: “If indeed the mode of action is non-genotoxic, 

then the default linear threshold model used by the petitioners to estimate the IUR may not 

be appropriate, and a non-linear (threshold) approach may provide a more accurate 

representation of the dose-response relationship between nPB exposure and cancer 

endpoints.” The sentence is true as a logical proposition, but note well the operative 

words: “If,” “may,” and “may.” Where is the evidentiary support for these expressions of 

possible alternatives to linearity and human relevance? 

• Female mice and rats showed tumorigenic responses, but not male animals 

(conveniently omitting mention of the excess skin cancers in male rats)—if EPA 

wishes to analyze the 185 current HAPs for those that show similar “inconsistent” 

results (or no positive cancer bioassay at all!), it will find this is a common finding, 

including among substances already known via epidemiology to be carcinogenic in 

male and female humans.

• Mouse lung tumors may be caused by a species-specific pathway, causing “an 

increase in mostly benign lung tumors”—this might be interesting speculation, were 

it not for the fact (not mentioned in the Gradient report) that 7 of the 9 tumorbearing animals found in the 62.5 ppm exposed group had malignant neoplasms.

• No epidemiologic data are available to prove human carcinogenicity beyond 

doubt—again, this statement applies to the vast majority of all currently-listed 

HAPs. Epidemiology is to true cancer risk what Galileo’s telescope was to the 

enumeration of Jupiter’s moons—a good way to detect the obvious and to miss what 

is there but is harder to see.

• Most of the in vitro tests on 1-BP did not show mutagenicity—if “weight of evidence” 

means nothing more than the number of studies on each hand, perhaps this is a 

useful statement, but the report offers no refutations of the positive mutagenicity or 

DNA-damage tests, only to invoke a possible high-dose phenomenon.

• 1-BP caused immunosuppression in the test animals—NTP agrees with this 

observation, but Gradient’s inference that immunosuppression should decrease 

concern is bizarre, as this is a second and independent risk factor for cancer in 

humans.
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Again, I note with chagrin that every single reference in the Gradient report about “high 

dose” effects evidences utter disregard for U.S. workers. I call particular attention to the 

statement (p. 8) that “the exposure concentrations used by NTP (62.5-500 ppm) are several 

orders of magnitude greater than those modeled for ambient air ... [and therefore] may be 

qualitative with regard to potential carcinogenic effects, but not reliable for quantitative 

extrapolation from animals to humans.” I have to ask: what species are the U.S. workers for 

whom no extrapolation from bioassay concentrations is needed because they are 

currently being exposed above 62.5 ppm? EPA needs only to interpolate between the 

62.5 and the 125 ppm exposures to see that the positive cancer bioassay is prima facie

“relevant to humans”! (I also note that the Gradient statement immediately above 

acknowledges all EPA needs to know: the hazard identification step for 1-BP is complete, 

and it is “reasonably anticipated to cause cancer in humans.”) 

Finally, I note that nowhere does either manufacturer in its comments attempt to 

cast doubt on the fact that 1-BP is a human neurotoxin at levels far below that used in the 

animal cancer bioassay. Although Albemarle does attempt a partial refutation of the 

finding by Li et. al of diminished vibratory sense in workers at approximately 7 ppm (pp. 2-

4 of the January 2015 letter to Dr. Barone at OPPT), nowhere does either manufacturer 

mention the 2004 study by Ichihara et al., which documented complete loss of vibratory 

sense in workers exposed to as little as 1.1 ppm 1-BP 2. Therefore, in addition to being a 

reasonably-anticipated human carcinogen, 1-BP is a known human neurotoxin, and must 

be listed as a HAP on that basis alone. 

Policy Implications: 

 

 Enviro Tech would have EPA believe that its customers understand that 1-BP is not 

a “drop-in” replacement for perchloroethylene, and that for this and other reasons, its sales 

are declining. Perhaps EPA should accept Enviro Tech’s own sales figures and future 

projections as accurate, even though the former are not verifiable in the public record3 and 

the latter are, of course, self-generated speculation. But Enviro Tech is one of hundreds of 

suppliers, distributors, and traders of this chemical (a search on the site www.molbase.com

 

2 That study examined 23 workers whose geometric mean time-weighted average exposure was 2.92 ppm; 15 

of the workers showed loss of vibratory sense in either fingers, toes, or both. 

3

Enviro Tech offers to help EPA obtain copyrighted reports about 1-BP importation quantities, but provides 

no back-up for its domestic-production estimates. 
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indicates at least 260 such suppliers), some of whom certainly do tout 1-BP as a drop-in 

replacement for Perc (see,. e.g., http://www.modelcleanersonline.com/solution.html). 

 Enviro Tech would have EPA believe that IF domestic use has indeed declined from 

8.861 million pounds per year in 2012 to 8.159 million pounds in 2014, and that IF that 

trend continues, that somehow the “out of date” information provided by petitioners 

renders 1-BP “not a HAP.” I suggest that EPA look at production figures for the 185 

currently-listed HAPs, and see how many (or how few...) of them are consumed in 

quantities above 8 million lbs/yr., before paying any attention to this non sequitur. 

 Enviro Tech would have EPA believe that listing 1-BP as a HAP would drive 

customers to use trichloroethylene. I suggest that EPA instead consider the market failure 

it has allowed to persist for at least the past several years: customers currently are misled 

by the manufacturers of 1-BP to purchase what they prominently advertise as “EPAapproved and not considered [a] hazardous air pollutant” (see p. 4 of my March 8 

comments to this docket). If customers fail to appreciate quantitative differences in risk 

within substances on the HAPs list, that is a problem, but surely that is far less of a problem 

than leaving one animal carcinogen and human neurotoxin on the list and leaving another 

one off, for no apparent reason other than that one was in production 25 years ago when 

Congress compiled the original list. 

Conclusions: 

 The manufacturers of 1-BP are asking EPA to believe that if the Agency does not list 

the substance as a HAP, exposures will decline. This proposition is unbelievable on its face 

(more likely, exposures will increase, which presumably is the goal of thwarting this 

petition), but it is also irrelevant to the listing criteria. 

Other than the affront of considering workers to be unworthy of mention, the most 

problematic statement in the recent comments is this one (p. 9 of the Enviro Tech 

comments): “little to no benefit will be achieved... should nPB be deemed a HAP.” 

Purportedly, Enviro Tech somehow knows that users of 1-BP are already complying with 

emissions limits that would be set in the future if EPA was first to list 1-BP and then later 

to regulate it. 

 Instead, I offer the following truism, which follows directly from the Enviro Tech 

statement: “little to no cost will be incurred... should nPB be deemed a HAP.” If Enviro 

Tech is correct, there is no reason not to follow NTP, ACGIH, and other expert bodies and 

summarize the science about 1-BPs hazard by listing it among the other 185 HAPs. 
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 But at this stage, EPA should not be concerned with either the benefits OR the costs 

of some hypothetical future regulation. It has been asked to render a science-policy 

opinion about whether a substance belongs on a list. The benefits of listing 1-BP as a HAP 

are simple: it amply meets the listing criteria in the Clean Air Act, and therefore citizens 

will no longer be misled that it is “non hazardous.” 

Thank you for the opportunity to comment on this important issue; I would be happy to 

provide any further information by request. 

Sincerely, 

Adam M. Finkel, Sc.D., CIH 

Senior Fellow and Executive Director, Penn Program on Regulation, University of Pennsylvania Law School and

Clinical Professor of Environmental Health Sciences, Univ. of Michigan School of Public Health 

(affiliations listed for purposes of identification only)