Cosmo Specialty Fibers, Inc.

The Site is in Cosmopolis, Washington and the main mill portion is located on the south bank of the Chehalis River. Weyerhaeuser constructed the pulp mill at the site in 1957. The mill made paper grade products until 1962, when Weyerhaeuser converted production to dissolving and specialty grade pulp. The mill made pulp by using magnesium sulfite to cook wood chips, then bleached the pulp using chlorine dioxide and other chemicals.

Weyerhaeuser operated the mill until September 2006, when production shut down. The company mothballed the facility the following year in preparation of selling the mill. In May 2011 the mill resumed operation as Cosmo Specialty Fibers (Cosmo). In December 2022, Cosmo shut down its production and transferred ownership to Charlestown Investment. The mill has remained shut down while the new owner pursues investors to re-start mill operations. However, chemicals used for the pulping process remain stored at the site. Staffing at the site has significantly reduced during that time and both power and water were shut off in the fall of 2024. Cosmo stores about 800,000 gallons of chemicals at the site in preparation for the intended re-start.   

Constructed in 1957, the facility predates environmental laws and regulations, including the 1976 Resource Conservation and Recovery Act (RCRA) and the 1989 Model Toxics Control Act (MTCA). Over the years, there have been documented releases, including the following:
• Liquid chlorine leak from a chlorine car on October 27, 1979.
• Release of magnesium oxide dust from a recovery bypass valve on December 1, 1979 for a duration of 5 hours.
• Spill of about 1,000 gallons of red liquor to the stormwater system on February 6, 1980. Red liquor is a mixture of spent pulping chemicals and organics specific to the sulfite pulping process.
• Spill of sodium hydroxide from a railcar off-loading in February 1995, resulting in groundwater exceeding the pH 12.0.
• Spill of acidified water to the ponds on January 6, 1998, resulting in pH measurements as low as 1.0 in the adjacent ditches.
• About 16 leaks in the wastewater pipe over the last 10 years, with the most recent leak discovered on September 12, 2023 at the residential area. The pipe is made of wood stave and runs about 2.5 from the mill through the town of Aberdeen and Cosmopolis.
In addition to documented spills, the November 2017 Sediment Study found elevated levels of dioxin and furans in the vicinity of the mill’s outfalls.

Contamination at the site has not been fully investigated. Future remedial investigation (RI) will provide additional information on the location and types of contaminants at the site.