Ask the Expert Question-and-Answer Archive

by Ron Joseph

December, 2003

Determining if Subject to MACT and NESHAPS

Q. Background ... We are a job shop with a five-stage surface preparation system followed by powder painting and curing. We have zinc occuring in solids accumulating in floor drains from the two cleaning stages of the surface preparation process.

I am working on the indirect discahrge permit renewal application and must check off if the facility is subject to NESHAP. I do not believe the zinc is over 10 TPY, but I must calculate the amount of zinc? Must I indicate "Yes" to NESHAP since I have zinc but do not know where it is coming from?

Second, my PM10 is less than 100 TPY, but I have no idea if zinc is over 10 TPY, however, I currently believe it is less than 10 TPY because of the amount of waste paint disposed per year. Is the facility subject to NESHAP on the air side of things?

A. Thanks for your email. You did not tell me which MACT standard you are trying to evaluate. In fact, currently I don't know of a standard that would apply to a powder coating operation. By next year we will have the Miscellaneous Metal Parts and Products NESHAP and that might well apply to you.

In general, you should know that the 10 tons/year threshold for any NESHAP refers to the "Potential to Emit" (PTE) and not actual emissions. If you think that you produce sufficient zinc so that your PTE will exceed 10 TPY, then you would be subject to a MACT. I'm assuming that you are considering zinc to be a hazardous air pollutant (HAP), although I'm not sure that this is the case. Have you checked the list of 188 chemicals on the HAP list? If zinc is not on the list then you are free and clear.

What is zinc is on the list?

First, the NESHAPs apply to air pollutants, not to hazardous waste. Since you are disposing the zinc as a solid waste, it cannot be an air pollutant. For this reason alone you should not need to consider this in your NESHAP determination.

Suppose the zinc were an air pollutant and you were to calculate your PTE and found that theoretically you could produce more than 10 TPY of zinc, yet you know that your actual waste is only 1 TPY of zinc, you could accept a permit condition that does not allow you to produce more than, say 2 TPY. You would have your agency write a permit that is federally enforceable and limits you to 2 TPY of zinc. Under such a condition you would not need to worry about a NESHAP. You would be considered a Synthetic Minor.

My guess is that the entire zinc issue does not apply, because it is not an air pollutant, but first check it out!

Jeffrey, before you take my answer as final, please first confirm this with an environmental consulting firm. Although I'm knowledgeable on NESHAPs and environmental regs for surface coatings, I don't deal with discharge permits, and am not an expert on making the final determination.