Sec. 15.18.04.05. Compost Classification

A. A compost product is classified as a General Use, Limited Use, or Restricted Use compost as shown in §§B-D of this regulation.

B. General Use Compost.

(1) General Use compost may not exceed the following specifications:

Parameter	Parameter Limit All limits apply to product leaving composting facility.
(a) pH (range)	6.0-8.0
(b) Heavy metals (maximum)
(i) Arsenic	41 mg/kg dry wt.
(ii) Cadmium	39 mg/kg dry wt.
(iii) Chromium	1200 mg/kg dry wt.
(iv) Copper	1500 mg/kg dry wt.
(v) Lead	300 mg/kg dry wt.
(vi) Mercury	17 mg/kg dry wt.
(vii) Molybdenum	18 mg/kg dry wt.
(viii) Nickel	420 mg/kg dry wt.
(ix) Selenium	36 mg/kg dry wt.
(x) Zinc	2800 mg/kg dry wt.
(c) PCBs	5 ppm
(d) Man-made inerts (maximum) >4mm, <13mm	2 percent dry wt.
(e) Film plastic >4mm	2 percent dry wt.
(f) Process to further reduce pathogens (required for compost from municipal solid waste or manure)	pass

(2) A General Use compost:

(a) Shall pass through a 12mm (1/2 inch) screen;

(b) Shall be stabilized;

(c) May not have an objectionable odor; and

(d) May be distributed as a soil conditioner for use by the general public or for any use allowed by this chapter.

C. Limited Use Compost.

(1) A Limited Use compost may not exceed the following specifications:

Parameter	Parameter Limit All limits apply to product leaving composting facility.
(a) pH (range)	6.0-8.0
(b) Heavy metals (maximum)
(i) Arsenic	41 mg/kg dry wt.
(ii) Cadmium	39 mg/kg dry wt.
(iii) Chromium	1200 mg/kg dry wt.
(iv) Copper	1500 mg/kg dry wt.
(v) Lead	300 mg/kg dry wt.
(vi) Mercury	17 mg/kg dry wt.
(vii) Molybdenum	18 mg/kg dry wt.
(viii) Nickel	420 mg/kg dry wt.
(ix) Selenium	36 mg/kg dry wt.
(x) Zinc	2800 mg/kg dry wt.
(c) PCBs	10 ppm
(d) Man-made inerts (maximum) >4mm	4 percent dry wt.
(e) Film plastic >4mm	2 percent dry wt.
(f) Process to further reduce pathogens (required for compost from municipal solid waste or manure)	pass

(2) A Limited Use compost:

(a) Shall pass through an 18mm (3/4 inch) screen;

(b) Shall be stabilized;

(c) May not have an objectionable odor; and

(d) May only be distributed for use by a commercial, agricultural, institutional, or governmental operation, or for restricted use as provided by this chapter.

D. Restricted Use Compost:

(1) A Restricted Use compost may not exceed the indicated maximum level for any heavy metal or trace element, as follows:

(a) Arsenic	75 mg/kg dry wt.
(b) Cadmium	85 mg/kg dry wt.
(c) Chromium	3000 mg/kg dry wt.
(d) Copper	4300 mg/kg dry wt.
(e) Lead	840 mg/kg dry wt.
(f) Mercury	57 mg/kg dry wt.
(g) Molybdenum	75 mg/kg dry wt.
(h) Nickel	420 mg/kg dry wt.
(i) Selenium	100 mg/kg dry wt.
(j) Zinc	7500 mg/kg dry wt.

(2) A Restricted Use compost:

(a) May not be a hazardous waste, as defined in COMAR 26.13.02.03;

(b) May not be stockpiled or disposed of unless authorized by the Maryland Department of the Environment;

(c) May not be distributed or sold to the general public;

(d) Is restricted to distribution for use as a final, intermediate, or alternate daily landfill cover, as provided by COMAR 26.04.07, or on marginal land or in land reclamation efforts if applied at rates not to exceed limits established in Table 2 of Regulation .12 of this chapter; and

(e) Includes any compost exceeding any parameter limit for Limited Use compost, as provided in Regulation .05C of this chapter, or any compost designated by the registrant as Restricted Use classification.