(a) Environmental laboratories shall examine proficiency test samples supplied by the department or by a proficiency testing provider recognized by the department pursuant to subdivision (i) of this section. Laboratories shall conduct the specified examinations and submit the results to the proficiency sample provider for all analytes for which the laboratories are approved or seeking approval, and for which samples have been supplied.

1. (1) The department shall announce its schedule for mailed proficiency test sample distribution as soon as practicable after the first day of each approval year. Distribution frequency and dates shall be included in this announcement. The department shall specify, in letters distributed with samples, the department's test result scoring criteria. Laboratories participating in the department's proficiency testing program, shall report test results to the department no later than on the dates specified by the department for each manner of result submission (i.e., hardcopy or electronic). No extensions shall be granted. Laboratories whose results are received after the deadline shall be considered to have achieved unsatisfactory performance in the proficient test event. Laboratories participating in a recognized proficiency testing provider(s)' proficiency testing program, other than the department's program, shall arrange with that provider to have test results forwarded to the department.
2. (2) To obtain or maintain approval for a given analyte, an environmental laboratory shall attain satisfactory performance in at least two of three consecutive scheduled or unscheduled proficiency test events in which it has participated. Such events shall take place at least 30 calendar days apart.
3. (3) To obtain or maintain approval for the potable water - total coliforms analyte, for which proficiency testing requires qualitative analysis, an environmental laboratory shall maintain a score of at least 90 percent, without reporting a false negative result for at least two of three consecutive scheduled or unscheduled proficiency test events in which it has participated. Such events shall take place at least 30 calendar days apart.
4. (4) To obtain or maintain approval in contract laboratory protocol (CLP) analyses, an environmental laboratory shall be evaluated on both proficiency testing performance and conformity to the contract requirements of the CLP data package submitted.

(b) Performance in examining an individual chemical or physical analyte shall be evaluated as follows, for a natural blank test sample:

1. (1) Satisfactory performance shall be a result, reported with or without the term “less than,” and having a value less than or equal to the detection limit specified by the department, or, if no detection limit is specified, the method detection limit.
2. (2) Unsatisfactory performance shall be a result, reported with or without the term “less than,” greater than the detection limit specified by the department, or, if no detection limit is specified, the method detection limit.

(c) Performance in examining an individual chemical or physical analyte shall be evaluated as follows, for a synthetic blank test sample:

1. (1) Satisfactory performance shall be a result reported with the term “less than,” and having a value less than or equal to the detection limit specified by the department, or, if no detection limit is specified, the method detection limit.
2. (2) Unsatisfactory performance shall be a result reported with or without the term “less than,” and having a value greater than detection limit specified by the department, or, if no detection limit is specified, the method detection limit.

(d) Performance in examining an individual chemical or physical analyte shall be evaluated as follows, for a spiked or natural test sample:

1. (1) For data sets examined by the standard statistical procedures described in subdivision (g) of this section and having a relative standard deviation lower than 34 percent:

   1. (i) satisfactory performance shall be a result within the 99-percent confidence interval about the statistical mean; and
   2. (ii) unsatisfactory performance shall be a result outside the 99-percent confidence interval about the statistical mean.
2. (2) For data sets examined by the standard statistical procedures described in subdivision (g) of this section but having a relative standard deviation of 34 percent or higher, the relative standard deviation of the data set used for determining the 99-percent confidence interval shall be set at 34 percent, or a value derived from the scientific literature. Satisfactory and unsatisfactory performance shall be as described in paragraph (1) of this subdivision.
3. (3) For data sets evaluated by using a reference laboratory panel, the statistical mean and 99-percent confidence interval shall be derived from the reference laboratory data set, after standard statistical analysis. Satisfactory and unsatisfactory performance shall be as described in paragraph (1) of this subdivision.

4. (4) For data sets evaluated using an interval about the assigned value and defined by a fixed percentage of the assigned value, fixed percentages shall be set based on the department's determination of the reliability, precision and accuracy of the methods used, and:

   1. (i) satisfactory performance shall be a result within the fixed percentage interval about the assigned value; and
   2. (ii) unsatisfactory performance shall be a result outside the fixed percentage interval about the assigned value.

5. (5) For data sets evaluated using published linear regression equations to predict the mean and standard deviations:

   1. (i) satisfactory performance shall be a result within the interval of the predictive mean, plus or minus two predictive standard deviations for potable water analytes, or plus or minus three predictive standard deviations for other matrices; and
   2. (ii) unsatisfactory performance shall be a result outside the interval described in subparagraph (i) of this paragraph.

(e) Performance in examining an individual bacteriological analyte for which quantitation is required shall be evaluated as follows:

1. (1) For negative coliform and/or standard plate count test samples, including sterile samples, samples containing bacteria not detectable by the method and samples containing bacteria not producing positive reactions with the required verification procedures, satisfactory performance shall be a result reported as a value lower than the method detection limit. Unsatisfactory performance shall be any other result.

2. (2) Performance in examining an individual bacteriological analyte for which quantitation is required shall be evaluated as follows, for a positive inoculated test sample:

   1. (i) Satisfactory performance shall be a result within the 99-percent confidence interval about the statistical mean for Most Probable Number (MPN) and Membrane Filter (MF) coliform data, and within the 95-percent confidence interval about the statistical mean for standard plate count data.
   2. (ii) Unsatisfactory performance shall be a result outside the 99-percent confidence interval about the statistical mean for MPN or MF coliform data, and within the 95-percent confidence interval about the statistical mean for standard plate count data.

(h) Performance in examining potable water bacteriological samples qualitatively shall be evaluated based upon the known presence or absence of total coliform group members of Escherichia coli (E. coli). Satisfactory performance shall be a result correctly indicating the presence or absnce of total coliform bacteria, and correctly identifying E. coli, if present. Unsatisfactory performance shall be a result incorrectly identifying the presence or absence of total coliform bacteria or E. coli.

1. (1) The department may recognize a proficiency testing provider to offer and score results of proficiency testing samples for purposes of obtaining New York State environmental laboratory accreditation pursuant to this Subpart, provided:

   1. (i) the proficiency testing provider has submitted sufficient documentation to enable the department to determine that the provider adheres to standards for design, production, testing, distribution, data analysis and quality assurance that are at least equivalent to, or more stringent than, the department proficiency testing program's, and applies scoring systems identical to the department's;
   2. (ii) the proficiency testing provider demonstrates it has policies and procedures in place to protect the integrity of its proficiency testing program and prevent fraud in its administration;
   3. (iii) for analytes and sample types with EPA proficiency testing participation standards, the proficiency testing provider possesses a certificate or other documented approval demonstrating compliance with such EPA standards; and
   4. (iv) the proficiency testing provider agrees to supply the department with test scores, and any such other information and documentation requested to resolve any issues concerning compliance with this Subpart.
2. (2) The recognition granted to a proficiency testing provider pursuant to this subdivision may be withdrawn at any time if the department finds the provider no longer meets the criteria set forth herein, or has failed to provide the department with sufficient information and documentation to permit determination or demonstration of compliance or noncompliance with this Subpart.

(i)