FAMILY OF MATERIALS EXAMPLE #1 - API 5 

STEP PROCESS (1)

R-1

R-1

R-1 R-5

R-5

R-5 C1

A.

B.

C.

EQUIPMENT

Chemistry 

Step

Presence of 

HAPs 

/UHAPs

A Table 1 

HAP

B NA

C HAP

Isolated drum storage 

(2)

Isolated drum storage 

Isolated drum 

storage 

R-1

R-1

R-9 C1

R-5 C1

D1

1

D1

1

D.

E.

D HAP

E HAP

Notes: 

(1) Intermediates A, B, C, D and final product E are totally different chemicals made from totally different raw materials. 

(2) Material must be isolated prior to next step because of process safety concerns

Question: Given that intermediates A, B, C and D are isolated in drums, are they (and final product E) in the same Family of Materials?

Isolated drum 

storage 

Attachment A
FAMILY OF MATERIALS EXAMPLE #2 

A.

B.

EQUIPMENT Process Presence of HAPs 

/UHAPs

A Table 1 HAP 

generated

(HAP used for cleaning)

B NA 

(HAP used only for 

R-1

R-1

R-5 C1

R-5 C1

D11

D11

(HAP used only for 

cleaning)

Process A and Process B use the same CMPU

Process A uses raw material X and a solvent (water) to make product Z

Process B uses raw material X and raw material Y and a solvent (IPA) to make product W

Product A generates a Table 1 HAP as a byproduct 

Product B does not generate a Table 1 HAP, but uses a HAP for equipment cleaning

These products have similar end uses, but different applications.

Attachment A
Process A

FAMILY OF MATERIALS EXAMPLE #2 

Table 1 HAP + HAP (Cleaning)

N

R1

O

+

Initiator #1 

N

R1

O

N

+

Water

Note: No Table 1 HAP in Process B

Process B

N1

N

R1

O

+ R2

N

R3

O

N2

+ HAP (Cleaning) Initiator #2 

IPA

Attachment A
FAMILY OF MATERIALS – EXAMPLE #3 

•The company packages and sells a 

variety of specialty polyolefins. A large 

number of customers buy the polyolefins, 

many wanting a slightly different molecular 

weight, degree of saturation, solvent, etc.

• Emission profiles differ somewhat 

because (i) addition times for Reactant A 

Reactant A

Solvent A

or

Solvent B

Polyolefin

(HAP) control molecular weight, (ii) Solvent 

A may produce Table 1 HAP emissions 

Product C, while Solvent B does not, etc.

Product D,

etc.

Product Z

Attachment A
FOM EXAMPLE #4 - Pharmaceutical 

Production 

Raw Material X1 + Raw Material Y1 Phrma A

MeCl2

MeOH

Raw Material X2 + Raw Material Y2 Phrma B MeOH

Notes: 

1. The same CMPU is used to make Phrma A and Phrma B

2. Pharmaceutical products Phrma A and Phrma B have different pharmacological properties or treat different medical 

conditions or diseases. They are both regulated as 2 distinct products and processes under FDA regulations.

Questions:

1. Are the Pharmaceutical products Phrma A and Phrma B in the same family of Materials?

2. What criteria should be used to answer the above question?

3. Given that Phrma A and Phrma B are somewhat different compounds (including, for example, the case where they 

are isomers) but have clearly different pharmacological properties or treat different medical conditions or diseases, 

would they belong to the same Family of Materials?

Attachment A
FOM & Deminimis Cut-off Example #5 – Biological Active 

Pharmaceutical Production 

• A batch process uses 30 lbs/yr Table 1 metal HAP and approximately 30 

lbs/yr of a non-Table 1 metal HAP

• Material from this process is isolated in drums until it is formulated and 

packaged into injectable syringes at the same facility

• The formulation process does not involve any HAPs

• The definition of a CMPU implies that the formulation/packaging process is 

not part of the initial batch process and therefore is not regulated by CMAS 

• FOM implies the opposite

• If the above processes were located at a major source, the 

formulation/packaging process would not be regulated by the Pharma 

MACT because that rule does not contain the FOM language

• EPA has created a contradictory and confusing situation by incorporating 

both “family of materials” and “isolated intermediate” language into the 

CMAS rule 

Attachment A