June 1996



The Indiana Pollution Prevention and Safe Materials Institute (IPPI) worked with a large manufacturer of motor vehicle freight equipment to analyze areas within the company where hazardous chemical use and emissions could be reduced or eliminated. The project developed around the company's use of sealants and caulks, which are used to waterproof seams and joints of freight hauling equipment.


The company fabricates sheet metal, I-beams, and tubular steel into freight hauling equipment. The process involves extensive cutting and welding as well as painting of the finished equipment.


The manufacturing process of concern centered around the use of caulks and sealants, which are used in large quantities to waterproof the freight hauling equipment's many seams and joints.


One of the company's key environmental concerns is air emissions. The caulks and sealants used in the freight hauling equipment industry traditionally are formulated with volatile organic compounds (VOCs). Among the VOCs used to manufacture the caulks and sealants, are several hazardous air pollutant (HAP) chemicals such as toluene, xylene, and ethyl benzene.


IPPI began its study to reduce hazardous chemical use within the company by collecting material safety data sheets for all caulks and sealants used by the company. Each hazardous chemical (composing the makeup of each product) was entered into a computer data base. The Institute then collaborated with the company to collect and tabulate purchase invoices representing each different caulking sealant. This analysis led to a full accounting of the specific pollutants and their total use and emissions within the company. Once the use calculations were made, the Institute reviewed and analyzed alternative caulks and sealants which were low in VOC and HAP compounds. The task was to select low VOC and HAP coating products as candidates to replace the more hazardous caulks and sealants currently used.

The low VOC and low HAP-containing candidates needed to exhibit the following performance characteristics in order to prove to be successful alternatives:


The currently-used caulks and sealants generated an aggregate total of 80,000 pounds of VOC emissions. This total included the following emissions:

	Chemical	Emitted

	toluene         29,000
	xylene          31,500
	ethyl benzene    8,800
	other VOCs      10,700

The Institute found three caulking sealant candidates which met the aforementioned performance characteristics:

Overall, the adoption of any one of the three candidates to replace those used in the current system will yield the following:

	Chemical	Reduction

	toluene  	  100% 
	xylene  	  100%
	ethyl benzene  	  100%
	other VOCs  	  25%

Total, aggregate VOC emissions will be reduced, on average, by 90% or 72,000 pounds (36 tons).

The estimated cost savings are as follows:

	Geocel Pro 920   ($37,726)
	DAP Alex Plus  	  $2,905
	Tite Bond  	  $407,920

Obviously the Tite Bond product shows the most dramatic savings. Thus, it is recommended that Tite Bond should be the first of the candidates to be tested.

It should be noted that the price quotes for these materials were "first" quotes only. Therefore, these candidate costs are estimated to be higher than actual, competitively-bid costs. If the company were to adopt a blend of all three products, each serving in a special niche (as are the six different caulks the company currently uses), then, the aggregate, average savings to the company would be more than $125,000 per year.


The opportunity assessment demonstrates that dramatic VOC emission reductions can be achieved (90% reduction totaling 72,000 pounds), and yet, yield a potential aggregate savings averaging $125,000 per year.

It is hoped that this P2 Brief can serve as a guide to other companies which desire quality performance, air pollutant emission reductions, and dramatic cost savings.