The company grew steadily over the next 40 years but when local forests had been logged off and when profits could no longer support further investments and updates it became uncompetitive.

Hundreds of millions of dollars have since been spent in South West Michigan cleaning up the last Allied Paper mill site and the PCB pollution caused by this company.

[4] In January 1931, Alex G. Gilman, now president, reported at the annual stockholders meeting that Allied Paper Mills had been profitable in 1930 and noted that the outlook in 1931 was more favorable.

[7] On 2 September 1955 it was announced that the Allied Paper Mills board had approved a plan to be acquired by the Thor Corporation, a maker of household appliances.

A special shareholders meeting was called for 3 October so they could vote on this plan, which offered $46 per share of common stock.

At this time, Allied was the fifth largest employer in Kalamazoo County, Michigan and had made a net profit of $1,367, 410 in 1954.

[8] The shareholders approved the plan and on 2 December 1955 Arnold H. Maremont, president of Thor Corporation announced the transaction was complete.

D. R. Curtenius, who had been the president of the Allied Paper Mills, was retained in a consulting capacity by the new paper-making division of Thor.

They invested heavily, including construction of a new research building on Alcott Street in Kalamazoo, but sold the Bryant Mill to the St. Regis Paper Company in 1946.

Also in early 1957 Allied announced they would build a large new pulp mill on the north side of Cork St in Kalamazoo but this addition never occurred.

This was called Allied-Egry Business Systems and was under direction of Jack Kennedy, former vice president for sales at The Egry Register Co.[15] Eight business forms companies had been acquired with plants in Kalamazoo, Michigan Dayton, Ohio; Denison, Texas; Kansas City, Missouri; Leipsic, Ohio; Los Angeles, California and Petersburg, West Virginia.

[17] Also in 1963 the Allied Paper Corporation started construction of a $12 million pulp mill in Jackson, Alabama.

Most of the planned 100,000 tons of paper pulp produced each year at Jackson would be shipped by railroad to the Kalamazoo mills.

[27] A new 18,000 square feet (1,700 m2) headquarters building for the papermaking division of SCM was constructed on Portage Road in Kalamazoo during 1974 and 1975.

[29][30][31] In 1986, SCM was bought by Hanson plc, a British conglomerate, but they had no interest in the paper business, which was no longer as profitable as it had been in the past decades.

[32] In 1988, Michael Gallenberger, an Illinois businessman, spent most of the year negotiating with Hanson to buy the Bryant Mill in Kalamazoo.

On December 31, 1988, Hanson completed the sale of the Bryant Mill to Michael Gallenberger, who formed a company called Performance Papers Inc.

[39] After this closure, GAF Corporation attempted to lease the Bryant Mill site and use it for manufacturing of roofing felt.

[40] After sitting empty and unused for some 7 years, demolition of the Bryant Mill started in 2004, paid for by the State of Michigan.

The concrete channel containing Portage Creek was also removed and there is now no trace that a large paper mill has ever operated on the site.

[41][42] The only Allied Paper Corporation building remaining in Kalamazoo, Michigan is the 1975 headquarters on Portage Road, which has become a community center.

In addition, the PCBs had traveled along Portage Creek and into the Kalamazoo River, causing significant contamination all the way downstream to the dam at Allegan, Michigan.

[43][44] SCM Allied Paper was held legally responsible for cleanup of the lagoons and ponds used by the Monarch and Bryant Mills.

Through acquisitions this responsibility transferred sequentially to the following corporations: Hanson PLC, Millennium Chemicals, Lyondell and finally LyondellBasell, headquartered in the Netherlands.

Cleanup of sediment in the Kalamazoo River at Plainwell and Otsego was accomplished in 2008 and 2009, partly funded by LyondellBasell.

[45] A March 2008 report prepared for the Michigan Department of Environmental Quality (MDEQ) detailed analytical information about the Bryant-Monarch Superfund Site.

[48] A May 2010 article in Bloomberg Markets on how bankruptcy law is being used to avoid the cost of environmental cleanup included the PCB contamination caused by Allied Paper.