Attachment E-5

Using Representative Sampling and Extrapolation to Evaluate Compliance with Generator 

Recordkeeping, Reporting, and Monitoring Requirements Not Contained in a Permit

I. Generator Recordkeeping and Reporting Requirements Unrelated to Opacity

New Cingular currently estimates that there are approximately 435 Legacy AWS 

facilities with generator recordkeeping or reporting requirements, unrelated to opacity 

monitoring, that are not contained in a permit. A contractor made a preliminary evaluation of the 

available generator information and the applicable regulations to provide this updated estimate in 

response to EPA’s request. New Cingular has not determined whether these requirements are 

federally enforceable and reserves the right to assert a lack of enforceability or other defenses 

with respect to these requirements. 

The number of facilities may change as a result of the data collection and compliance 

evaluation processes that New Cingular will undertake during the audit. For instance, the audit 

may provide new information about the generators at a facility, indicating that a recordkeeping 

or reporting requirement applies. Similarly, the auditor may reach a different interpretation of an 

existing regulation. The audit may also show that the recordkeeping or reporting requirement in 

a particular jurisdiction is not federally enforceable. In other jurisdictions, such as Alabama, 

New Cingular might not learn of a recordkeeping requirement until after the state agency 

receives and evaluates a generator notification that the Company submits to correct a potential 

violation that it discovers, if any. 

The following example illustrates how the extrapolation process authorized by section 

I.B.3 of the protocol would work, if the Company chooses that option. The sample size is 

obtained by applying a 90% confidence level along with an error level of plus or minus 7.5% to 

the facility universe. Assuming the audit confirmed that 435 facilities was the correct number of 

facilities subject to a recordkeeping or reporting requirement not contained in a permit, New 

Cingular would review the records for 95 facilities which is 22% of the total. 

Next, the Company would perform site visits at 20% of the sampled locations (i.e., 19 

facilities) to check the accuracy of the information and records sent to the auditors. The 

locations visited would be representative of the types of facilities (e.g., cell towers) having 

generators subject to such requirements. To evaluate the compliance status of the remaining 340

facilities, New Cingular would extrapolate the “fail” rate of the 95 sampled facilities.

II. Monitoring and Recordkeeping Pertaining to Opacity

New Cingular has not yet determined how many, if any, of the generators located at the 

Legacy AWS facilities are subject to federally-enforceable monitoring and/or recordkeeping 

requirements pertaining to opacity that are not contained in a permit. To the extent that there are 

such requirements and New Cingular elects to use statistical sampling to evaluate generator

compliance with those requirements, the Company would undertake a process similar to the one 

outlined below, making adjustments as necessary to help ensure the reliability of the results. 
2

New Cingular would begin by identifying those jurisdictions in which Legacy AWS 

facilities are located and which have federally-enforceable monitoring and/or recordkeeping 

requirements pertaining to opacity. Within each of those jurisdictions, the Company would then 

identify all of the facilities that have generators subject to such requirements that are not 

contained in a permit. That would define the population of relevant facilities (the “Pool”). Next, 

it would group those facilities together and randomly sample from that population.

The number of facilities sampled would depend upon the size of the Pool. Specifically, 

New Cingular would use the size of the Pool to calculate the sample size necessary to enable the 

Company to be at least 90% confident that the compliance rate of the sampled facilities would be 

within 7.5%, plus or minus, of the actual rate of compliance of the Pool. 

For each of the sampled facilities, New Cingular would collect and review the relevant 

records. Next, the Company would supplement its records review by performing site visits to 

20% of the sampled facilities to check the accuracy of the information and records sent to the 

auditors. The locations visited would be representative of the various facility types in the 

sample. The Company would then extrapolate the “fail” rate of the sampled facilities to those 

facilities that had not been sampled.