4. Letter of Warning

A letter of warning is a formal, written notification issued for certain first‐time violators or violations of a lesser nature.  In most cases letters of warning will be sent through the regular mail.  If deemed necessary, the letter of warning may be sent certified mail. The letter is written in lieu of a notice of violation for the types of violations listed below. All letters of warning will contain one or more deadlines for the party receiving the letter to take appropriate action, and Web page addresses and phone numbers to aid the recipient in obtaining compliance assistance. Deadlines contained in letters of warning will reflect the time typically needed to complete the work required. In some cases, the work cannot be completed within a 90 day time frame (e.g., monitoring required during a specific time frame, after the initial 90 days). Some work will itself exceed 90 days (e.g., cleanup of a large dump where the responsible party is cooperating with the regional office.) In either case, contact the appropriate program. An enforceable document such as a compliance agreement may be used when the regional office needs to give the responsible party an extended time frame to achieve compliance. In all cases, the letter of warning will act as a reminder that future compliance is required, and that continued or additional violations will trigger a more assertive response. The office issuing the letter of warning is responsible for tracking compliance with the letter’s requirements and taking additional action if the noncompliance persists. Conference, conciliation and persuasion will continue throughout the letter of warning compliance timeframe, as does the department’s emphasis on compliance assistance. These standards are essential throughout all phases of compliance and enforcement work, and do not conflict with the use of stronger measures that must be applied in instances where noncompliance persists. This does not mean the department will reduce its demands in regard to actions needed to reach compliance, but rather the department will continue to provide a positive, problem‐solving environment and assist an entity in violation to examine options for achieving compliance.

Violations subject to the department issuing a letter of warning include:

Note that a notice of violation may be issued in place of a letter of warning depending upon the specific circumstances involved. For example, if a first‐time violator fails to submit critical information, and that failure is deemed an important violation of federal requirements, the department’s response may be a notice of violation.

A letter of warning may be combined with an inspection report for efficiency. The dual purpose letter must contain the following elements and are included in the standard letter in Section 4.A. Forms:

On occasion, Letters of Warning will be rescinded. See Chapter 5 for LOW and NOV rescission procedures.

4.1 Air Pollution

See Section 5.1 for criteria for Letters of Warning, Notices of Excess Emissions and Notices of Violations.

4.2 Public Drinking Water Branch

Drinking Water Letters of warning shall be employed as established in the general guidance of this manual, except for program‐specific modifications detailed in the Public Drinking Water Branch’s Escalation Policy. Letters of warning may also be issued for other low priority or first time violations at the discretion of regional office employees. Additional specific uses of letters of warning can be found in the Escalation Policy (see Appendices). Regional offices may use discretion to issue letters of warning in other circumstances in which a notice of violation is not required.

4.3 Hazardous Waste

Letters of warning are used when the inspection results in Class I violations or Significant Operational Compliance violations (see Section 2.1). Class I violations are listed in the linked document.

Letters of warning should be sent to the facility, note the violations, request documentation of return to compliance or a schedule for returning to compliance, and give a 30‐day response due date. The inspector will evaluate the facility’s response to the letter of warning. If the response documents a return to compliance, then the inspector will send a return to compliance letter to the facility. No further action is warranted. For those facilities that do not return to compliance or don’t respond, the inspector will call the facility representative. If the telephone call prompts an immediate response demonstrating compliance, the inspector will send a return‐to‐compliance letter to the facility. If the facility does not immediately demonstrate compliance, the inspector will issue a notice of violation and proceed with a normal referral. See the appendices for a list of Hazardous Waste citations with recommendations for LQG's and SQG's.

4.4 Land Reclamation

There are no formal letters of warning issued by the Land Reclamation Program. The program will follow the protocol outlined in Section 3.4 of this manual when using conference, conciliation or persuasion to obtain compliance. The inspection report generally contains the steps necessary for the alleged violator to return to compliance.

4.5 Solid Waste

An letter of warning may be issued for any violation that is considered serious enough to require corrective action within a specified time frame and a follow‐up compliance inspection, but is not listed as an acute violation or an high priorty violation (as defined in the 3.A Appendices ‐ Solid Waste Management Program’s 4-3 High Priority Violation List), or is another violation serious enough to warrant the issuance of an notice of violation.

In addition to the general guidance regarding letters of warning, an illegal disposal investigation report , or IDIR may be used rather than an letter of warning to document an illegal solid waste or scrap tire dump. Regardless of which format is used, the same information must be provided to the responsible parties and copied to the Solid Waste Management Program. The following information must be included on all letters of warnings and illegal disposal investigation reports, whether they are issued to a permitted facility or to an responsible party conducting an illegal activity, except where indicated below:

The following are examples of violations of the Missouri Solid Waste Management Law and Regulations that may be subject to an letter of warning. These are not all‐inclusive lists. Contact the Solid Waste Management Program’s Compliance and Enforcement Section for violations not covered below, repeat violations of a similar type or nature, and all other enforcement questions. Entities who fail to comply with compliance deadlines may be issued an notice of violation and referred to the Solid Waste Management Program for enforcement action. However, prior to issuing an notice of violation, the Solid Waste Management Program must first be contacted to obtain concurrence for a referral. If there is any question regarding whether a violation could be considered a criminal violation, contact the Solid Waste Management Program’s Compliance and Enforcement Section to discuss the situation before correspondence is sent to the responsible party.

Solid Waste Violations

Record Keeping ‐ Upon request, an entity must provide all records required by statute, regulation, or permit. If they fail to do so, the entity may be issued an letter of warning. If an entity has not historically kept records, they will be required to begin keeping records immediately. If an entity has failed to properly maintain their records and keep them accessible, they will be required to submit the subject records within 10 calendar days of the Department’s request.

Permitted Facilities ‐ Violations must be corrected by the next inspection or within a reasonable deadline established by Department staff. Examples include, but are not limited to: negligent maintenance of landfills or processing facilities where no public nuisance or health hazard exists, leachate seeps contained within the landfill property boundaries (not flowing off the property or into waters of the state), and moderate ponding of water, lack of vegetation, or lack of sufficient daily cover on landfills. Significant cover violations should be discussed with the program to determine the appropriateness of an letter of warning versus a notice of Violation(i.e., the extent of the violation, whether the violation is repetitive in nature, and other related 4-4 negative impacts such as odor complaints, litter or vectors. All these should be considered in the choice of the compliance tool).

Illegal Dumping ‐ Contractors found illegally dumping less than 40 cubic yards of construction and demolition waste will be issued an letter of warning or an illegal disposal investigation report . Cleanup of the illegal dump will be required within a period of 30‐90 days. Additional time may be granted for extenuating circumstances as long as progress is documented. Contact the Solid Waste Management Program for approval of compliance periods greater than 90 days. Disposal receipts must be submitted within 15 days following completion of the cleanup. If the illegally dumped waste is egregious, creates a public nuisance, health hazard, or off‐site environmental threat, or the dumping was conducted by a recalcitrant or repeat violator, an notice of violation may be issued instead.

Payment of Fees ‐ Entities failing to pay fees on time will be issued an letter of warning for their first violation and be required to submit the subject fees and any associated documentation within 14 days of receiving the letter of warning. An example is solid waste tonnage fees and reports. Repetitive violations will result in the issuance of a notice of violation.

Guidance for citations and related enforcement action recommendations for sanitary landfills and processing facilities are available at:

Scrap Tire Violations

Record Keeping ‐ Upon request, an entity must provide all records required by statute, regulation, or permit. If they fail to do so, the entity may be issued an letter of warning. If an entity has not historically kept records, they will be required to begin keeping records immediately. If an entity has failed to properly maintain their records and keep them accessible, they will be required to submit the subject records within 10 calendar days of the department’s request.

Permitted Facilities ‐ Violations must be corrected by the next inspection or within a reasonable deadline established by department staff. Examples may include, but are not limited to: moderate non‐compliance with scrap tire storage and fire regulations.

Illegal Dumping ‐ An individual not associated with a permitted scrap tire facility, a scrap tire hauler or a collection center found illegally dumping less than 500 scrap tires on their own property for the first time will be issued an letter of warning or an illegal disposal investigation report. Cleanup of the illegal dump will be required within a period of 30‐90 days. Additional time may be granted for extenuating circumstances as long as progress is documented. Contact the Solid Waste Management Program for approval of compliance periods greater than 90 days. Disposal receipts must be submitted within 15 days following completion of the cleanup. If the dump is egregious, creates a public nuisance, health hazard, or off‐site environmental threat, or the dumping was conducted by a recalcitrant or repeat violator, a notice of violation may be issued instead.

Unpermitted Haulers ‐ Tire haulers caught operating without a permit for the first time will be issued an letter of warning provided evidence indicates the scrap tires were properly disposed of. The tire hauler must submit a completed permit application and all associated documentation and fees within 15 days of receiving the letter of warning. Tires haulers caught hauling without a permit who were previously permitted or who were otherwise knowingly hauling without a permit should be issued a notice of violation.

Collection centers discovered using unpermitted haulers for the first time will be issued an letter of warningprovided evidence indicates the scrap tires were properly disposed of. The collection center must submit documentation that they have contracted with a permitted tire hauler or have implemented an approvable disposal option within 15 days of receiving the letter of warning. Entities discovered utilizing an 4-5 unpermitted hauler who have done so in the past or who were otherwise knowingly utilizing an unpermitted hauler should be issued a notice of violation.

4.6 Water Criteria for Issuing a Letter of Warning

Certain circumstances may not warrant the issuance of a Letter of Warning or a Notice of Violation even when violations are documented.  A Letter of Warning is not warranted if it is a first-time violation of 10 CSR 20-8.020, 10 CSR 20-8.200, or violations of permit conditions that do not meet the requirements for issuing a Letter of Warning or a Notice of Violation (Chapter 5). If these violations are found, the inspector should mark the facility in noncompliance in MoCWIS and the inspection report.

The inspector should also:

Issuance of an inspection report with required actions, and tracked in MoCWIS as Inspection Report, Required Action, is an appropriate response for the following violations, and may be used when there is no impact or there is no imminent threat to the environment and public health or other significant noncompliance that meets the criteria found in Section 4.6 or Section 5.6.  These required actions will not affect regional compliance rates.  

A letter of warning is not warranted for effluent violations identified during an inspection or file review if a facility has submitted and began to implement a department-approved plan of action to address the violation(s), and is in compliance with the approved implementation schedule.

Domestic Wastewater Treatment Facilities

Responsible Parties of permitted facilities receiving primarily domestic waste shall be issued an inspection report with required actions, and tracked in MoCWIS as Inspection Report, Required Action, when one or more - including but not limited to - the following criteria exist:

  1. The outfall is not marked in the field.
  2. Warning signs are not posted on all four sides of the perimeter fence surrounding the facility.
  3. Adequate fencing is not provided around the facility to restrict unauthorized entry and protect the facility from vandalism.
  4. The facility does not have a locked or lockable gate to restrict unauthorized access.
  5. The inner berm slopes are not maintained at less than a three to one slope.
  6. The facility did not have an all-weather access road.
  7. Deep rooted vegetation is discovered on the lagoon berm.

The issuance of a letter of warning is the appropriate first response for the following violations and may be used when there is no impact or there is no imminent threat to the environment and public health or other significant noncompliance that meets the criteria found in Section 5.6.

Domestic Waste Permitted Facilities

Responsible Parties of permitted facilities receiving primarily domestic waste shall be issued a Letter of Warning when:

  1. Based upon available records the discharge or activity results in the following conditions:
    Facilities with Monthly Reporting Requirements
    • One or more violations of the applicable monthly average or the weekly average effluent limitation of a specific parameter at a given permitted outfall by any amount. (If more than a single violation occurred, review the criteria for issuing a notice of violation in Chapter 5 to determine if the violations merit an a notice of violation instead.) For water quality based permitted effluent limitations that are below the minimum quantification level, or ML, and specifically listed in the Missouri State Operating Permit any value reported greater than or equal to the ML is a violation of the daily maximum limit. Reporting non‐detectable is acceptable for this category of effluent limitations and any value reported below the ML should be questioned.
    • One or more pH values that are outside the pH range of 5.0 to 10.0 with the exception of lagoon systems, which may exceed the upper pH limit during the summer months due to biological activity.
    • One or more monthly discharge monitoring reports are not submitted within 30 days of the due date.
    • DMRs submitted are missing data required by the Missouri State Operating Permit.

      Facilities with Quarterly Reporting Requirements.
    • One or more violations of the applicable monthly average or the weekly average effluent limitation of a specific parameter at a given permitted outfall by any amount. For water quality based permitted effluent limitations that are below the minimum quantification level and specifically listed in the Missouri State Operating Permit any value reported greater than or equal to the ML is a violation of the daily maximum limit. Reporting non‐detectable is acceptable for this category of effluent limitations and any value reported below the ML should be questioned.
    • One or more pH values that are outside the pH range of 5.0 to 10.0 with the exception of lagoon systems, which may exceed the upper pH limit during the summer months due to biological activity.
    • One or more discharge monitoring reports are not submitted within 30 days of the due date.
    • Quarterly discharge monitoring reports submitted are missing data required by the Missouri State Operating Permit

      Facilities with Annual or Semi‐annual Reporting Requirements
    • Any violation of the applicable monthly average or the weekly average effluent limitation of a specific parameter at a given permitted outfall by any amount. (If more than a single violation occurred, review the criteria for issuing a notice of violation in Chapter 5 to determine if the violations merit an notice of violation instead.) For water quality based permitted effluent limitations that are below the minimum quantification level and specifically listed in the Missouri State Operating Permit any value reported greater than or equal to the minimum quantification level is a violation of the daily maximum limit. Reporting non‐detectable is acceptable for this category of effluent limitations and any value reported below the minimum quantification level should be questioned.
    • One or more pH values that are outside the pH range of 5.0 to 10.0 during with the exception of lagoon systems, which may exceed the upper pH limit during the summer months due to biological activity.
    • The annual or a semi‐annual discharge monitoring report is not submitted within 30 days of the due date.
    • The annual or a semi‐annual discharge monitoring report submitted is missing data required by the Missouri State Operating Permit.
  1. Other reports (annual inflow and infiltration, construction completion, pretreatment, annual, etc.) are not submitted within 30 days from the date specified in the Missouri State Operating Permit.
  2. A responsible party fails to submit an application to renew their Missouri State Operating Permit within 180 days prior to the expiration.
  3. For a facility that has a marginal exceedance (less than 20) over their permit limit for fecal coliform or E.coli the facility should be issued an letter of warning. The letter of warning should identify that the facility needs to submit monthly monitoring to determine if the exceedance is a one time or regular occurrence. If the occurrence id regular rather than an isolated event, the facility needs to be issued an notice of violation and required to install disinfection equipment.

Land Disturbance Permitted Sites

Responsible parties of permitted land disturbance sites shall be promptly issued a letter of warning when:

  1. Best Management Practices have been implemented but are not being maintained to prevent
    sediment from eroding off‐site as required by the Missouri State Operating Permit and the Stormwater
    Pollution Prevention Plan and Stormwater discharges from the site have not resulted in:
    • A violation of the permitted limitation for settleable solids by a factor of 1.4.
    • A violation of the Missouri Water Quality Standards general or specific criteria.
  2. The responsible party fails to submit an application to renew the Missouri State Operating Permit for
    land disturbance activities within 90 days prior to the expiration date.


Animal Feeding Operations and Concentrated Animal Feeding Operations Permitted Sites

Responsible parties (owners or continuing authorities) of permitted animal feeding operations and concentrated animal feeding operations shall be promptly issued a letter of warning when:

Facilities and Sites Operating Without a Permit

Responsible parties (owners or continuing authorities) operating a water contaminant source (e.g. wastewater treatment system, land disturbance site, industrial stormwater site, classified animal feeding operation), without a permit shall be promptly issued a letter of warning if discharge/activity has not resulted in a violation of the Missouri Water Quality Standards or is not an imminent threat to public health and/or the environment. If the responsible party has been previously notified of the requirement to obtain a permit or the discharge/activity has resulted in a violation of the Missouri Water Quality Standards or is an imminent threat to public health and/or the environment please refer to 5.6 Criteria for issuing a Notice of Violation.

MS4 Permitted Sites

Enforcement Escalation Plan And Stormwater Complaint Protocol

This section will help department staff to:

NOTE: These efforts to more directly involve regulated MS4s in issue resolution do not relieve the department of obligations to enforce department permits.

  1. MS4 inspections based on complaints should result in a determination that the municipality involved is or is not a regulated MS4. See list of regulated MS4s at www.dnr.mo.gov/env/wpp/stormwater/sw-phaseii-communities.pdf
    • If not, proceed to Section II.
    • If so, is or is not the item of concern a violation of the MS4 permit. See general permit or sitespecific permit in respective folder on T drive.
    • If not, proceed to Section II.
    • If so, what is the description of the violation, how does it need to be addressed, what is the timeline for resolution? (See Section V of this document for inspection and enforcement protocols.) See MS4 Contact Info located at T:\MS4 Enforcement.
  2. Search Excel document MS4 Contact Info located at T:\MS4 Enforcement. Locate the MS4 permit number, county, region and contact information. Locate the MS4 permit number, county, region and contact information.
  3. Locate relevant documents on the T drive by region, county and permit number.
  4. Review the permit and the latest stormwater management program plan to determine if the issue should be addressed by the MS4 through one of the following local regulatory programs.

NOTE: The permit will indicate the requirements, and the stormwater management program plan will indicate the MS4’s intention of complying with those permit requirements. The stormwater management program plan may have deficiencies in one or more of the following areas to meet permit requirements:

  1. If yes to item 4. above, then:
    • Advise the key MS4 contact of the local MS4 permittee of violation, the MS4 action needed, and timeframe for the action.
    • Enter necessary action and timeframe into MoCWIS.
    • Determine outcome.
    • If MS4 permittee action is not effective within designated timeframe, initiate direct action through CC&P.
    • If the MS4 should be enforcing the issue and fails to do so, it may become necessary to address the issue directly. In this situation, hold the MS4 accountable for not enforcing relevant components of its MS4 program, as well as hold the violator directly accountable.
    • Issue letter of warning to the permittee and/or responsible party after consultation with Water
      Protection Program and perform a targeted inspection on one or more program components if
      circumstances warrant it.See item #11 below.
  1. If the MS4 is directly responsible for the issue, or if not directly responsible for the issue, but fails to enforce the MS4 program ‐ a violation of their own MS4 permit ‐ department staff will need to determine if the complaint or violation is, for example, due to:
    • Failure to control runoff pollution from municipal operations.
    • Failure to regulate, inspect or enforce non‐MS4 construction site land disturbance activities.
    • Failure to implement pollution prevention and good housekeeping in municipal operations, or PPGH.
    • Failure to train municipal employees in PPGH or as inspectors for other aspects of the permit.
    • Failure to map all stormwater outfalls.
    • Failure to regulate, inspect or enforce against illicit discharges.
    • Failure to perform pre‐site design reviews for water quality control in post‐construction runoff measures ‐ such as green infrastructure and low impact development practice.
    • Failure to regulate, inspect and enforce post‐construction runoff requirements.
    • Failure to follow up enforcement directives.
    • Failure to submit the MS4 permit application or renewal application.
    • Failure to submit the updated stormwater management program plan.
    • Failure to submit annual report.
    • Failure to develop or implement required ordinances/regulatory options for:
      1. Illicit discharge detection and elimination program.
      2. Construction site land disturbance program.
      3. Post‐construction (permanent) runoff management program.
      4. Industrial stormwater runoff program (Phase I communities of Kansas City, Independence and Springfield.
      5. Failure to perform water quality monitoring per TMDL requirements (if applicable).
      6. Failure to perform water quality monitoring requirements (mandatory for Phase I communities of Kansas City, Independence and Springfield).
  1. If after reviewing the permit and the stormwater management program plan, department staff have any questions about expectations for MS4 program performance, they should contact the MS4 Coordinator in the Water Protection Program in the central office at 573‐751‐1300.
  2. If any issue poses an imminent health threat or significant and obvious violation of water quality standards, department staff must take immediate action to ensure the problem is corrected and staff should take steps to coordinate subsequent enforcement action with the enforcement section in central office. Immediately issue a notice of violation.
  3. Failure to implement ordinances, map outfalls and implement other major components of the MS4 program may be considered significant violations – especially if not completed within the designated time of the permit (five years of initial permit issuance for Phase IIs and three years within initial permit issuance for the Phase I municipalities of Kansas City, Independence and Springfield. Issue a letter of warning, then follow up with a notice of violation if issue persists.
  4. Additional violations may include (but are not limited to):
    • Failure to include all aspects of municipal operations in the pollution prevention and good
      housekeeping program such as:
        1. Departments of Parks, Streets and Solid Waste.
        2. Vehicle or fleet maintenance, salvage yards, salt storage and other activities not requiring a separate industrial stormwater permit.
    • Failure to keep records.
    • Failure to modify the SWMP as appropriate
  5. If it becomes necessary to do a brief inspection, refer to their MS4 permit, SWMP and annual report documents and use the Missouri MS4 SWMP Checklist located at T:\MS4 Enforcement. If it is determined that a more detailed inspection or comprehensive audit is needed, use the audit questionnaire located at T:\MS4 Audits\MS4 Inspection Checklist Template and coordinate audit with central office MS4 permit coordinator.

4.A Forms

Letter of Warning template (Word® document) Hazardous Waste Citation Guide (PDF document)

  End Chapter 4 Next Chapter