Chapter 3 – How to Write a Pollution Prevention Plan

Step Three: Determine the Baseline

Any benchmark or baseline should be expressed as a pollution-to-production ratio. It will also be used to determine the cost of the pollution per unit of product.

A baseline needs a relevant unit of product for each product that is manufactured with the chemicals being studied. The unit of product must be an accurate measure of a characteristic of the product. If a process is used for the same part at all times, then number of pieces will make a good unit of product. However, if the process works on several parts, then a more specific measure will be needed to determine units of product, such as surface area or weight.

Units of Measure

How much waste is produced per product? Identifying the correct means of measuring the performance of a manufacturing process is one of the most important steps in pollution prevention planning. The measurement accurately portrays what is happening in the process and provides meaningful data to use in the options analysis step. Pinpointing and solving problems would be difficult without measurement, as would be documenting the impact of pollution prevention. Feedback from measurement will also help in making decisions on facility policies, developing new technologies, and choosing additional pollution prevention options.

The unit of product must be carefully chosen. Generally, valid units of product are count (numbers of pieces), surface area (square feet), volume (cubic feet), etc. Examples of units that are not valid are sales and run time. The unit of product must relate directly to the product or service being measured. In addition, in order to obtain accurate data on the amount of pollution generated during a production run or during a measured time period, rejected product must be included in the calculation of the production volume. This is why sales are not a good indicator of production rate. Conversely, run time is not a good indicator of production because a machine or a process may be operating, but the product is not necessarily being produced nor is waste being generated. Sales underestimates production volume and run time overestimates it.

The Production Ratio

It is necessary to develop a basis of comparison for chemical waste generated in the production process over time. Simply comparing waste generated from year to year can be misleading if there was a significant change in the levels of production involving the chemical being targeted. Production ratio (PR) is used to normalize changes in production levels. It is calculated by dividing the production level for the reporting year by the production level for the previous year. Once a production ratio is determined, it is used as a factor when comparing target chemical waste generated between the two years.

Production Ratio Example

Production Level ChangePR
10% Increase1.1%
10% Increase0.9%

Production Ratio Example 3-1

A facility paints 1,600 parts in Year A.
It paints 1,800 parts in Year B.

The production ratio is: 1,800 / 1,600 = 1.13

Simply using the units to determine the PR may not give an accurate result if the parts are not identical. In that case, a more specific attribute must be used such as surface area, weight or other relevant measure.

Production Ratio Example 3-2

A facility fabricates control housings from sheet metal. There are two production lines in operation. One fabricates the front panel and the other fabricates the sides and back of the housing. The exteriors of the two parts are coated and then screwed together. The exterior surface area of the front panel is 12 square inches and the exterior surface area of the back and sides is 36 square inches.

Number of Parts Manufactured

Year BYear A
Note: numbers include parts rejected
Line 1 (front panels)1,2541,093
Line 2 (back & side panels)1,2081,006

Total Surface Area Coated per Production Line (sq. in.)

Year BYear A
The Production Ratio is: 58,536 / 49,332 = 1.19
Line 115,04813,116
Line 243,48836,216

Data Gathering

Either during or after a team has been organized, the performance of the current manufacturing processes must be determined. As a minimum, the processes that use or generate Toxic Release Inventory (TRI) chemicals are targeted for pollution prevention. This will be critical for the team to calculate a baseline for future comparisons and must be done prior to options analysis. An important first step is to decide the accurate and relevant units of measurement for the processes involved. The next section provides more details on measuring waste and pollution generation.

Data Gathering for Current Operations

For each and every process that uses a chemical reportable on the TRI Form R, gather and verify information related to the chemical’s waste generation and releases. This information must be comprehensive in order to be as accurate and useful as possible. It should include information related to the product being manufactured, the process, the volume produced, and all associated costs.

Product Data

There should be a description of the product(s) or service(s) related to the chemical being addressed. This may include information about desired quality and the reason why the product manufacturer requires the use of a TRI chemical. Customer input may be desired or required for specifications. Pollution prevention planning is a good way to question the design of a product and ask why the chemical is needed. Are there customer specifications or product quality issues that need to be considered? These will be factors when options are analyzed for pollution prevention.

Process Data

In order to further pinpoint how and why a chemical waste is being generated, process information must be gathered. Data on the process should include a description of the major steps.

Finding out how employees are involved in the process is often helpful. This can include information on employee function, training and safety/health considerations. Also, obtain whatever documentation is available about the process such as vendor literature, chemical analysis, preventive maintenance schedules, equipment specifications, etc. Any or all of the information will be needed for the options analysis step that studies the alternatives for making the process more efficient, thus using less raw material or generating less waste or pollution.

Chemical Handling Data

Because waste can be generated as a result of transfers and spills, data should be gathered on how chemicals are stored, transferred, packaged and otherwise dispensed. These operations may be a part of the manufacturing process or they may be auxiliary operations that occur elsewhere in the facility.

Cost Data

During option analysis, in order to calculate the costs, savings and payback of any pollution prevention changes must be gathered on all operations that involve the TRI chemicals in question. Many hidden costs in the use of a chemical are instituted in overhead or department charges. However, these numbers must be isolated and identified in order for the option analysis to be comprehensive.

Some costs to consider are those related to environmental compliance. This includes compliance issues such as analysis of waste, treatment of waste, license fees and the cost of disposal. As burdensome as these costs might be, they are only a fraction of the cost to manage TRI chemicals.
Many of these environmental compliance functions can be done externally or internally. If they are internal costs, remember to include the cost of the time it takes staff to perform these tasks.

Another cost is the purchase of the chemical. Add to this the cost to transport the chemical. This must include not only any external charges to get the chemical to the facility but the internal cost to transport it within the facility. Then add the cost to store the material, including the cost of the space it occupies.

Auxiliary costs to properly store and maintain the chemical must be included. Add any cost for temperature or humidity controls required for the chemicals storage and use. In addition, there might be costs to maintain the equipment that stores or transports the chemical, including preventive maintenance. Costs for risk management include the following: insurance to protect against losses caused by accidental release and injury; health and safety equipment and training requirements so employees can work with the chemical as safely as possible; and for some chemicals significant costs due to absenteeism caused by perceived or real health effects of the chemical.

Example 3-3:

From Example 3-1, toluene is used to thin the paint at one pound of toluene per gallon of paint. This toluene is released to the air as the paint dries. In Year A, 100 pounds of toluene was released in this way when the 1,600 parts were painted. So if Year A is the baseline year, the pollution to production ratio is 100 divided by 1,600 or 0.063 pound of toluene released per part painted. If the toluene costs $1 per pound, the cost is 6.3 cents per part painted.

During Year A, tests were performed and it was discovered that paint quality did not deteriorate by using 0.80 pound of toluene per gallon of paint. This reduced use of toluene per gallon of paint released 90 pounds in Year B. The pollution/production ratio is 90 divided by 1,800 or 0.05 pound of toluene released per part painted, and the cost is 5 cents per part. So compared to the baseline year, this is a savings of 1.3 cents per part, or $23.40 for 1,800 parts.

Finally, intangible costs should be assessed and recorded by asking:

  • Are there any community concerns?
  • Are there employee health or safety concerns about using the chemical?
  • Are there emergency response concerns regarding the use of the chemical?
  • Does the chemical contribute to unpleasant production work areas (i.e. odors)?
  • Are there product marketing disadvantages?

In order to obtain a baseline of the present situation, all this information must be gathered and be effectively organized. This can be done with charts, graphs, matrices, etc. Each facility will have a unique system to organize the data to fit its needs.

Production ratios and baselines must be determined for each process that generates the chemical being studied.

In addition to determining a baseline for measuring the cost of waste generation per unit of product, it is also essential to identify and document current and past pollution prevention efforts. Documentation of efforts will allow the pollution prevention team to avoid repeating work unnecessarily and also provides the groundwork for future feasibility studies if changes in technology or increasing costs of environmental management make yesterday’s discarded ideas more attractive today.

Next is to sum all the chemical waste generated data and divide it by the amount of production that generated those chemicals. The result of this operation is the amount of waste or pollution that is generated per unit of product.

Sources for Data Gathering of Waste and Pollution Information

Waste generated from production processes can assume a variety of forms. Most notable among these are air emissions, process wastewaters, hazardous waste and scrap. It is important to be aware of all forms of waste that are produced through manufacturing to ensure an accurate assessment of a production process. One good approach for gathering this information is to develop a material balance or process map for target chemicals to account for each waste stream that comes from the process. This can start with a sketch showing the flow of raw materials, products, wastes and releases involving the target chemical. Make sure to include streams for wastes that are recycled, treated or otherwise managed on-site.

A common engineering principle is that what goes into a system must come out in some form or another. By measuring the material inputs, the total outputs that must be accounted for can be identified and through process of elimination, the unknowns can be determined. In some cases, the data needed to fully measure the amount of each waste stream may not be available. In these cases, it becomes necessary to use engineering judgment and knowledge of the production process to develop reasonable estimates of how the system is operating. This occurs more often with water and air releases, particularly “fugitive” (non-stack) air releases.

Hazardous Waste

The primary information source for waste shipped off-site, whether to be recycled, treated, or disposed, is the hazardous waste manifest. The manifest provides the type and quantities of hazardous wastes shipped. For mixed wastes or sludge that contains target chemicals, a useful tool for determining the fraction of the mixture that consists of the target chemical is to review the waste profile submitted to the off-site hazardous waste management firm when the waste stream was approved for acceptance. The waste management firm your facility is contracted with should supply, upon request, copies of the results of waste analysis that was performed when a shipment was received.


Information for scrap waste can be found on the bill of lading for each shipment. These are often used in place of the hazardous waste manifest for wastes such as scrap metals, scrap circuit boards or spent lead-acid batteries that are sent to a metals recycler. Similar to the hazardous waste manifest, the bill of lading will provide the type and quantities of scrap materials shipped. Product design specifications may be needed to help estimate the amount of the target chemical contained in the total waste shipped.

Wastewater Discharged to POTW

To discharge wastewater to a publicly-owned treatment works (POTW) generally requires an Industrial Discharge permit, which will include limits on the pollutant concentrations allowed in the wastewater discharge. Facilities are required to perform periodic sampling and analysis of their wastewater discharge to ensure compliance with the limits set. This information can also be used to estimate annual levels of a target chemical that is discharged to a POTW by using the concentration levels determined in sampling along with the cumulative volume of wastewater discharge from the facility. Some facilities perform in-house sampling and analysis on a more frequent basis than required by their permit. These results provide a good tool for estimating the volume of a target chemical that is discharged to a POTW.

Stack Air Emissions

Facilities that are required to hold air emissions permits should find that their permit application contains a great deal of information to help estimate a target chemical’s volume of releases through stack air emissions. Each manufacturing process that vents emissions through a stack is required to be thoroughly described in the air permit application, with information regarding the chemicals used, the throughput of the process and the emissions associated with the process. The calculations contained in an air permit application are performed on a basis for potential to emit, which assumes constant operation of the manufacturing process equipment and does not include emissions reductions due to pollution control equipment. Therefore, any use of air permit application data must include appropriate changes to reflect the actual operating conditions of the process.

Facilities that are not required to hold air emissions permits may estimate their stack air emissions using their knowledge of process conditions and materials balances. Quarterly or annual tests of stack emissions may be worthwhile to perform to provide data to compare to estimates.

Fugitive Air Emissions

Fugitive (non-stack) air emissions can be difficult to determine directly. They are commonly estimated through a materials balance with fugitive emissions representing the last remaining unknown after all other outputs have been directly measured or estimated. If a facility employs an industrial hygienist, he or she may have information on employee exposure levels that can also be used in estimating fugitive air emissions.

On-site Waste Management

There are several ways that wastes are managed on-site. Some wastes can be recycled, such as spent solvents or used oils and lubricants. Most facilities keep track of how many batches are processed by the recycling equipment or of the amount of regenerated material. Also track the amounts of solvents, used oils, or other flammable materials that are incinerated on-site. These should be identified in the air emissions permit application. Other wastes are treated on-site prior to disposal, such as spent acids and caustics or polymer waste. Information for measuring the amounts of waste generated should be obtained either from the treatment process description, or from direct observation of the process.

Some employees may be hesitant to take all of the necessary steps involved in gathering the information needed for a complete material balance, as it can initially appear to be a daunting task. A recommended first step in performing the material balance is to simply document material inputs minus the materials included in the product stream. This result will show the amount of waste that is generated and can serve as a driving force for finding the specific sources of waste in a process.