Further Explanation of Decision, February 2015 

This Memorandum provides EPA Region I's detailed analysis regarding the 

determination being made that Vermont's program regulating wastewater evaporation units is 

more protective of human health and the environment and therefore not less stringent than the 

federal approach. This supplements the analysis set forth in the Federal Register notice. 

Wastewater evaporation units (evaporators) (as further defined by Vermont) evaporate 

water using heat to reduce the volume of wastewater and to concentrate hazardous wastes. 

Vermont regulates these units using the conditions of its permit exemption for generator 

treatment in tanks and additional conditions designed to effectively regulate evaporators. EPA 

has analyzed whether the Vermont regulations are equally or more protective of human health 

and the environment than the federal regulations, rather than being less stringent. EPA has 

determined that they are more protective/stricter, thus being within the State's authority to 

maintain. See RCRA section 3009 (precluding only less stringent state requirements). 

To determine that the state regulations are stricter and not less stringent than the federal 

regulations, EPA has compared the state regulations to the federal regulations, including 

examining interpretations that have been made of the federal regulations (available in the 

administrative record and in RCRA Online). However, in line with the national policy: 

Determining Equivalency of State RCRA Hazardous Waste Programs, September 7, 2005 

(Equivalency Policy), EPA has not required that the state follow the same identical approach as 

the federal regulations. Rather, EPA has focused, "on whether the state requirements provide [at 

least] equal environmental results as the federal counterparts." ld. 

At the federal level, the wastewater treatment unit (WWTU) exemption has been 

interpreted to cover many hazardous waste evaporators. In the Cervino letter (Jan. 16, 1992), 

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EPA advised that any facility that has ever had a water discharge is considered to be subject to 

the exemption. EPA has further advised that all dry cleaning establishments may claim the 

exemption. Fisher letter, June 2, 1993. EPA also has advised that facilities with zero water 

discharge systems may obtain water permits whether or not required to do so by the water 

program, and then will qualify for the exemption. Elliott letter, Mar. 20, 1989. While this 

interpretation was first stated with respect to facilities switching from water discharges to zero 

discharge systems, it has been applied to allow facilities that never have discharged to the water 

to obtain water permits and thereby qualify for the exemption. 

Vermont is stricter than this federal approach in that it excludes wastewater evaporation 

units from being covered under its WWTU exemption. VHWMR § 7-103. Rather, it regulates 

them under its more protective generator treatment in tanks exemption. VHWMR § 7-502(o)(8). 

At the federal level, the only general RCRA requirement under the WWTU exemption is that the 

evaporator treatment occur in a tank or tank system (see 40 C.F.R. § 260.10 definition). 

Additionally, Vermdnt requires meeting the fuil range of generator requirements for large 

quantity generators (LQGs) and small quantity generators (SQGs ), such as requiring secondary 

containment around the tanks, contingency planning, and for large quantity generators, meeting 

the RCRA air emission control standards in 40 C.F.R. part 265, subparts AA, BB and CC. See 

VHWMR § 7-502(o) and cross-referenced provisions. Vermont is also stricter by more 

extensively regulating conditionally exempt small quantity generators (CESQGs). At the federal 

level, persons treating certain 0001 (ignitable) and 0003 (reactive) wastes in evaporators under 

the WWTU exemption also must follow specified safe handling requirements (see 40 C.P.R. § 

264.l(g)(6)). Vermont is stricter by requiring evaporators treating all hazardous wastes to follow 

such safe handling requirements. See VHWMR § 7-502(o)(8)(B). 

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The Vermont regulations for the generator treatment in tanks exemption are stricter than 

that federal exemption. Vermont imposes a general condition that treatment in evaporation units 

"shall result in the concentration of hazardous waste constituents for proper recycling or 

disposal, and not allow evaporation of the hazardous waste constituents into the air." VHWMR 

§ 7-502(o)(8)(A). Vermont requires as a condition for obtaining any RCRA permitting 

exemption that the generator be in compliance with all applicable federal and state air emission 

control requirements. !d. Vermont explicitly prohibits any "disposal" of hazardous waste 

through evaporation. VHWMR § 7-302(a). Finally, Vermont requires that any generator 

seeking to operate an evaporator must provide notice to the Vermont Department of 

Environmental Conservation (Department). VHWMR § 7-502(o)(l). As represented in the 

state's application for authorization, the Department then reviews and approves all notifications. 

When appropriate, the Department may impose additional case by case standards as a condition 

of approval. Vermont has reserved the right to add case by case requirements in VHWMR § 7-

312. 

Thus, the Vermont regulations are stricter than the federal regulations with respect to the 

many evaporators which qualifY for the federal WWTU exemption. However, there may be 

some evaporators that do not qualify for the WWTU exemption at the federal level. This 

generally could include facilities that have never discharged to the water, are not dry cleaners, 

and have not obtained zero discharge water permits. Under the federal approach, some of the 

facilities that do not currently have zero discharge water permits might obtain them and thereby 

also qualify in the future for the exemption. However, there may be some facilities that could 

never qualifY for the exemption. As part of the process of comparing the state regulations to the 

federal regulations, EPA has examined what the approach would be for such facilities at the 

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federal level, in particular whether such facilities could qualify for the federal generator 

treatment in tanks exemption. 

Since 1986, the EPA has generally allowed generators to conduct treatment in tanks (and 

containers) without permits, if they comply with all applicable generator tank (and container) 

management standards. 51 Fed. Reg. 10146 (Mar. 24, 1986). Since 1987, however, the EPA has 

advised that there is an exception to this general allowance in that "thermal treatment" by 

generators without permits is not allowed. Memorandum by OSW Director, Dec. 15, 1987. The 

resulting question is whether at the federal level evaporation is considered to be "thermal 

treatment" for purposes of the generator treatment in tanks exemption, thus requiring a thermal 

treatment permit, or is allowed to be conducted without permits in tanks by generators. 

Under the WWTU unit exemption, the EPA has determined that evaporators do not 

require thermal treatment permits. While thermal treatment units such as incinerators do not 

qualify for the WWTU exemption (see Olsen letter, Aug. 3, 1987), the Agency determined that 

evaporators should continue to qualify as 'treatment in tanks' under the WWTU exemption 

rather than being required to meet thermal treatment permitting standards. 56 Fed. Reg. 7134, 

7202 (Feb. 21, 1991 ). Under the WWTU exemption, the Agency has distinguished between 

higher risk units which use thermal treatment to destroy or treat the hazardous constituents in 

waste and units whlch only evaporate water so as to concentrate wastes. 55 Fed. Reg. 29230, 

29232 (July 18, 1990). The latter kind of units have not been required to obtain thermal 

treatment permits. Thus the approach followed by the EPA under the WWTU exemption has 

been to not classify evaporation units as "thermal treatment" units requiring thermal treatment 

permits. 

The EPA initially issued guidance that evaporators similarly could qualify for the 

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generator treatment in tanks exemption (i.e., did not need permits). Sasson letter, May I, 1987 

and Cervino letter, Jan. 16, 1992. However, in 1994, the EPA determined that thermal fuel 

blending treatment was not allowed under the generator treatment in tanks exemption. 

Memorandum from OSW Director, Oct: 17, 1994. Although the Oct. 11 Memorandum did not 

discuss evaporators, a note was then attached to the Sasson letter indicating that it had been 

superseded by the Oct. 17, 1994 memorandum. 

Although no such note was attached to the Cervino letter, we have assumed for purposes 

of the Region's authorization decision that the current EPA interpretation of the federal 

regulations is set by the note attached to the Sasson letter. The Region has thus assumed that at 

the federal level, evaporation treatment by generators without permits is not allowed under the 

generator treatment in tanks exemption, but rather is only allowed at facilities which qualify for 

the WWTU exemption. We believe that any regional decision should take account of the most 

stringent current national approach, unless and until that approach is changed at the national 

level. However, for the reasons explained below, the Region has nevertheless determined that 

the Vermont regulations are stricter, not less stringent than, the federal regulations. 

EPA has concluded that we should look at the overall RCRA program and assess the 

effect ofthe Vermont program across the board. In doing that, EPA has concluded that the 

Vermont program is stricter than any ofthe federal requirements with respect to wastewater 

evaporators. RCRA § 3009. Vermont consistently and strictly regulates all generator . 

evaporators by imposing hazardous waste management requirements and comprehensive air 

emissions regulations. This is stricter across the board than the federal approach, and thus 

should be allowed consistent with the national Equivalency Policy, which emphasizes that states 

may take different but equally or more protective approaches. 

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It also should be noted that the Vermont regulations require the same type of tank 

management standards and air emission control requirements as would be included in permits. 

Additionally, Vermont requires every generator operating an evaporator to submit a notice and 

obtain review of its operation, similar to what would occur if the generator was required to apply 

for a permit. Thus even if one looks at just those evaporators not subject to the federal WWTU 

exemption, Vermont arguably has equivalent permit-like controls in place. However, the Region 

need not decide this issue but rather may assess the stringency of the Vermont program across 

the board. When one takes account of the fact that the Vermont program is stricter than the 

federal requirements with respect to the many evaporators subject to the federal WWTU 

exemption, it is clear that the Vermont program is stricter across the board. 

The Region is not departing from national guidance in allowing this different State 

approach. Rather, the Region is following the national guidance set forth in the Equivalency 

policy, which says that States need not necessarily follow every federal approach. As explained 

in that policy, a State's obligation is to be equally or more protective than the federal program. 

In the circumstances presented here, where Vermont is being more protective than the federal 

approach, Vermont is not obligated to also follow the identical federal approach. 

The Region's decision does not violate the requirement in 40 C.F.R. § 271.13 that States 

must require permits for all hazardous waste management facilities required to obtain permits 

under 40 C.F.R. part 270. As noted above, the general approach that the EPA has taken to 

evaporators has been to allow them to operate without permits under the WWTU exemption. In 

Vermont's circumstances, section 271.13 should not be interpreted to rule out a state approach 

that is more protective overall than the federal approach. Also, the Region's decision is not 

contrary to the broad definition of "thermal treatment" in 40 C.F .R. § 260.10. EPA is not 

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opining that evaporators do not fall within such a broad definition. Rather, EPA is opining only 

that a State program that is more protective across the board is not less stringent than the federal 

program. As noted above, the federal program generally does not require evaporators to meet 

thermal treatment requirements (or most other RCRA requirements). Vermont may classify 

generator evaporators as not being thermal treatment that requires thermal treatment permits 

when this is part of an overall more protective state approach. 

There is no express federal statutory or regulatory requirement that generator evaporators 

must have permits. Rather, the RCRA statutory requirement is t!hat permits must be issued to 

treatment, storage and disposal facilities (TSDFs). RCRA § 3005. Vermont may take the 

different approach of strictly regulating all generator evaporators without being required to 

classify those not subject to the federal WWTU exemption as TSDFs. 

EPA emphasizes that the. Region's authorization decision will allow non-permitted 

evaporation treatment (outside of the WWTU exemption) only in Vermont. Such treatment will 

be allowed only because it has been federally authorized as "functionally" equivalent (part of an 

across the board more protective approach), and this federal authorization is being granted based 

on the particular strict requirements adopted by Vermont. EPA further emphasizes that this 

regional rulemaking has no implications for how other kinds of .. thermal treatment" will be 

regulated. Generally "thermal treatment" is not allowed without permits under either the 

generator treatment in tanks (and containers) exemption or under the WWTU exemption. In the 

Region's authorization decision, the Region is only allowing, subject to stricter Vermont 

standards, the same type of evaporation treatment that already has been allowed without permits 

under the WWTU exemption at the federal level and in the many states that follow the federal 

approach. 

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Finally, EPA notes that Vermont is stricter than the federal approach with respect to any 

evaporators located at Treatment, Storage and Disposal Facilities (TSDFs). These evaporators 

must always obtain RCRA permits in Vermont, since Vermont does not allow the use of the 

WWTU exemption for evaporators, and Vermont's treatment in tanks permit exemption for 

evaporators is limited to generators. 

Jeffry Fowley, Office of Regional Counsel, EPA Region I 

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