17.74.519    SAMPLING PROCEDURES

(1) All sampling procedures and laboratory analysis to verify the attainment of the decontamination standard for methamphetamine within inhabitable structures in order to remove an inhabitable property from the contaminated properties list, maintained by the department pursuant to 75-10-1306, MCA, or to obtain a certificate of fitness, pursuant to this subchapter, must be conducted in accordance with the NIOSH 9111 method, the Methamphetamine Indoor Decontamination Standards in 75-10-1303, MCA, and this section, with the following exceptions:

(a)  methanol shall be the only solvent accepted; and

(b)  samples shall not be composited.

(2)  The department may approve an equivalent method, in advance, if the method is at least as stringent as the method in (1).

(3) All samples identified in the department-approved assessment, work, or clearance plan shall be collected from within the inhabitable property.

(4)  The following shall be completed when sampling for methamphetamine contamination and to verify the attainment of the decontamination standards:

(a) all sample locations shall be photographed; and

(b) all samples, field blanks, and media blanks shall be recorded on the chain of custody.

(5) An assessment or clearance plan shall incorporate a sampling plan that follows an authoritative sampling approach, which uses professional judgment to target areas suspected to have the highest levels of contamination within the inhabitable property and unless otherwise approved by the department, shall include:

(a)  samples from each room or area within the inhabitable property known, based on credible evidence or documentation, to have contained a CML or to have been exposed to contamination from methamphetamine smoking; 

(b) at least two samples from each room or area within the inhabitable property where methamphetamine manufacturing or smoking is suspected to have occurred;

(c) at least one sample from each heating, ventilation, and air conditioning (HVAC) system's return side when such systems are present in the inhabitable property; and

(d) at least one sample from each exhaust fan when exhaust fans are present in the inhabitable property, unless assumed to be contaminated by the contractor.

(6) Each assessment plan shall include a minimum of two discretionary samples, to be collected and utilized at the methamphetamine certified contractor's discretion based on updated field observations. 

(7) If the encountered site conditions at an inhabitable property are different from the expected site conditions, the methamphetamine certified cleanup contractor may complete sampling in accordance with a modified plan.  An explanation of the unexpected conditions and sampling plan deviations shall be submitted to the department in the final report.

History: 75-10-1303, MCA; IMP, 75-10-1303, MCA; NEW, 2022 MAR p. 1812, Eff. 9/24/22.