Area Service Port Director
U.S. Customs Service
726 Exchange Street Suite 400 Buffalo, NY 14210

RE: Internal Advice #08/013; Classification of Dry Municipal Biosolids Cake

Dear Port Director:

The following is in response to your memorandum dated June 10, 2008, requesting Internal Advice in accordance with 19 CFR 177.11 (b)(4), concerning the proper classification of Dry Municipal Biosolids Cake, from Canada, under the Harmonized Tariff Schedule of the United States (HTSUS) initiated by letter dated March 1, 2008, by BCB International Inc., on behalf of its client, Woodington Systems Inc.


Dry Municipal Biosolids Cake is composed of the remaining solids after residential wastewater is treated at a municipal wastewater treatment plant. At the treatment plant the material is subjected to two treatment processes:

Anaerobic Digestion: biosolids are stored in a tank where micro-organisms break down organic material in the absence of oxygen. The biosolids are partially stabilized in that the concentration of pathogens and the amount of biosolids are reduced; and

De-Watering: reduces the volume and improves handling characteristics. The biosolids are normally watered before disposal or re-use. Once dewatered, the biosolids turn into semi-solid cake-like form with a solid content of 25-35%.

The biosolids are then transported to a beneficial re-use facilities. The Waste Transportation permit from the New York State Department of Environmental Conservation Division of Solid & Hazardous Materials lists the merchandise as “Sludge from Sewage or Water Supply Treatment Plant.”

After transport, the product is further stabilized through the addition of lime to dry and pasteurize the biosolids material. Once processed in this manner, the product becomes suitable for use in soil enhancement and is regulated as such.


Is the Dry Municipal Biosolids Cake consisting of partially stabilized sewage sludge, classified as fertilizer, in heading 3101, HTSUS, or as waste, in heading 3825, HTSUS?


Merchandise imported into the United States is classified under the HTSUS. Tariff classification is governed by the principles set forth in the General Rules of Interpretation (GRIs) and, in the absence of special language or context which requires otherwise, by the Additional U.S. Rules of Interpretation. The GRIs and the Additional U.S. Rules of Interpretation are part of the HTSUS and are to be considered statutory provisions of law for all purposes.

GRI 1 requires that classification be determined first according to the terms of the headings of the tariff schedule and any relative section or chapter notes and, unless otherwise required, according to the remaining GRIs taken in order.

The HTSUS headings under consideration are as follows:

3101.00.00 Animal or vegetable fertilizers, whether or not mixed together or chemically treated; fertilizers produced by the mixing or chemical treatment of animal or vegetable products

* * * * *

3825 Residual products of the chemical or allied industries, not elsewhere specified or included; municipal waste; sewage sludge; other wastes specified in note 6 to this chapter:

3825.20.00 Sewage Sludge

* * *

3825.90.00 Other

Note 5 to chapter 38 states “For the purposes of heading 3825, ‘sewage sludge’ means sludge arising from urban effluent treatment plants and includes pretreatment waste, scourings and unstabilized sludge. Stabilized sludge, when suitable for use as fertilizer, is excluded (chapter 31).”

In understanding the language of the HTSUS, the Explanatory Notes (ENs) of the Harmonized Commodity Description and Coding System may be utilized. The ENs, although not dispositive or legally binding, provide a commentary on the scope of each heading, and are generally indicative of the proper interpretation of the HTSUS. See T.D. 89-80, 54 Fed. Reg. 35127 (August 23, 1989).

EN 38.25 (C) states the following: “Sewage sludge is sludge arising from urban effluent treatment plant and includes pre-treatment waste, scourings and unstabilised sludge. The heading does not include stabilised sewage sludge when suitable for use as fertiliser (Chapter 31). However, those containing other materials harmful to agriculture (e.g., heavy metals), which make the stabilised sludge unfit for use as fertiliser, remain classified in this heading.”

In accordance with Note 5 to chapter 38, the Dry Municipal Biosolids Cake cannot be classified in heading 3825, HTSUS, if it is suitable for use as fertilizer. In determining whether an article is “suitable for use”, there must be evidence of more than casual, incidental, exceptional or possible use. See Headquarters Ruling Letter (HQ) 966691, dated May 3, 2004. As imported, the instant product contains pathogens that would be harmful to agriculture. It is not fully stabilized and requires additional treatment before it can be used as an unrestricted agricultural supplement. Furthermore, no evidence has been submitted that the merchandise is suitable for use as a fertilizer as imported. Therefore, the product cannot be classified in heading 3101, HTSUS.

Our decision is consistent with previous rulings classifying chemically or otherwise contaminated waste material under heading 3825, HTSUS. See New York Ruling Letter (NY) R03953, dated June 2, 2006, NY B89442, dated November 24, 1997, and HQ H018547, dated December 12, 2007.


By application of GRI 1 and Note 5 to chapter 38, Dry Municipal Biosolids Cake is classified in heading 3825, HTSUS, specifically in subheading 3825.20.00, HTSUS, which provides for: “Residual products of the chemical or allied industries, not elsewhere specified or included; municipal waste; sewage sludge; other wastes specified in note 6 to this chapter: sewage sludge.” The column one, “general” rate of duty is Free.

Duty rates are provided for the protestant’s convenience and are subject to change. The text of the most recent HTSUS and the accompanying duty rates are provided on the World Wide Web at

You are directed to mail this decision to the internal advice applicant, no later than 60 days from the date of this letter. On that date the Office of Regulations and Rulings will make the decision available to CBP personnel, and to the public on the CBP Home Page on the World Wide Web at, by means of the Freedom of Information Act, and other public methods of distribution.


Myles B. Harmon, Director
Commercial and Trade Facilitation Division