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                                                                      EXHIBIT 20
 
FOR FURTHER INFORMATION CONTACT:
Lawrence E. Gloyd
Chairman of the Board and Chief Executive Officer
Rockford, Illinois
815-962-8867
 
FOR IMMEDIATE RELEASE
September 23, 1996
 
                   CLARCOR TO ACQUIRE UNITED AIR SPECIALISTS
 
     ROCKFORD, IL, SEPTEMBER 23, 1996 -- CLARCOR Inc. (NYSE: CLC) today
announced the signing of a definitive agreement to acquire United Air
Specialists, Inc. (NASDAQ: UASI) in an exchange of common stock. CLARCOR is a
diversified marketer and manufacturer of mobile, industrial and environmental
filtration products and packaging products, while United Air Specialists is
primarily a manufacturer of environmental and industrial air filtration
products. As a result of the acquisition, United Air Specialists will become a
subsidiary of CLARCOR.
 
     The Boards of Directors of each company unanimously approved the
transaction which will be structured as a merger under which each fully diluted
share of United Air Specialists will be converted into 0.36986 shares of common
stock of CLARCOR. The exchange ratio is subject to adjustment based on the
actual number of fully diluted United Air Specialists shares outstanding at
closing. United Air Specialists currently has approximately 3,270,000 fully
diluted shares outstanding. CLARCOR currently has approximately 14,880,000
shares outstanding. To complete the merger, CLARCOR will issue approximately
1,210,000 shares of its common stock, bringing total outstanding shares to
approximately 16,090,000.
 
     To cover the costs of the merger, CLARCOR is expected to take a one-time
charge to earnings in an amount yet to be determined in the quarter the merger
is completed. CLARCOR had sales of approximately $290 million and net earnings
of $22.0 million for its fiscal year ended November 30, 1995, and expects fiscal
1996 sales to be approximately $330 million, excluding the UAS acquisition.
United Air Specialists had sales of approximately $40 million and net earnings
of $1.5 million for its fiscal year ended June 30, 1996.
 
     Larry Gloyd, CLARCOR's Chairman and Chief Executive Officer, said, "The
combination of CLARCOR and United Air Specialists will significantly strengthen
and expand our presence in the fast growing environmental and industrial air
filtration industry. In addition, we will have opportunities to increase
shareholder value through business synergies, such as the potential for filter
cartridges manufactured by our Airguard Industries operation to be used in
filter housings manufactured by UAS. We are also very pleased that the UAS
management team and key employees, with their tremendous experience and industry
reputation, will become a part of the CLARCOR team, and we look forward to their
significant contributions."
 
     Durk Rorie, United Air Specialists' President and Chief Executive Officer,
said, "We believe that the merger of UAS and CLARCOR is very positive for the
shareholders and employees of UAS. I doubt we could have found a company with a
better strategic fit for UAS than CLARCOR. There are many complementary
operational, geographic and product opportunities available as a result of the
combination of our two businesses."
 
     Consummation of the merger is subject, among other things, to approval by
the shareholders of United Air Specialists and regulatory approvals. It is
intended that the merger qualify as a tax-free reorganization to United Air
Specialists shareholders and be accounted for as a pooling of interests. The
merger is currently expected to close in early 1997. The three largest
shareholders of United Air Specialists, who collectively own approximately 50%
of the outstanding shares, have agreed to vote their shares in favor of the
merger.
 
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     CLARCOR, based in Rockford, Illinois, is a diversified manufacturer and
marketer of mobile, industrial air and environmental filtration products and
consumer packaging products sold to domestic and international markets.
 
     United Air Specialists, based in Cincinnati, Ohio, is engaged in the
business of manufacturing commercial and industrial air cleaners, energy
recovery systems, fluid contamination control equipment and high precision fluid
spraying systems.