PERMIT RATIONALE FOR REISSUANCE
Drexel Chemical Company
Tunica County
Tunica, Mississippi
Water NPDES No. MS0037621
February 2026

I.	FACILITY INFORMATION

Facility Name: Drexel Chemical Company
Facility Address: Tunica Industrial Park 
1099 Drexel Drive
Tunica, MS  38676    
Permit No.: MS0037621
SIC: 2879
Permit Writer: Samar Patel
EPD Branch: Water I Branch

II.	NATURE OF BUSINESS

The permittee formulates, manufactures, and packages agricultural chemicals.  This falls under 40 CFR Part 455 Subpart C Pesticide Chemical Formulating and Packaging Subcategory which states that there shall be no discharge of process wastewater pollutants to navigable waters. Noncontact cooling water and stormwater from the facility are covered under this permit.

III.	EFFLUENT AND RECEIVING STREAM FLOW DATA

Outfall 001— This is the non-contact cooling water outfall, which is no longer functioning or attached to any process that could discharge cooling water. As a result, this outfall has been removed from the proposed permit. 

Outfall 003—storm water from 2.6 acres of drainage area, all of which is impervious. Storm water drains from warehouse, production buildings, and property east of the facility to the “South Ditch.”  The outfall discharges to an unnamed tributary (7Q10 of zero) before combining with White Oak Bayou.

Outfall 004—storm water from 1.6 acres (1.4 acres of impervious surface).  The discharge (referred to as the “North Ditch”) consists of storm water from production buildings, office building, employee parking, and tank farms.  Runoff drains to an unnamed tributary (7Q10 of zero) before combining with White Oak Bayou.

The facility is located in the Yazoo River Basin.

IV.	303(d) ISSUES

White Oak Bayou is not listed on the 2024 Section 303(d) list of impaired water bodies.

In 2005, a TMDL was issued for the Yazoo River Basin to address the pesticides, DDT and Toxaphene. The goal established by the TMDL was for all water bodies in the basin to achieve the instream numeric water quality criteria for DDT and Toxaphene such that no fish advisories are necessary.  No load allocations were developed because both DDT and Toxaphene use were banned decades ago.  

In 2008, a TMDL was issued for the Yazoo River Basin addressing impairment due to siltation.  Point sources in the basin were not included in the document because no changes to their permits would be necessary (point sources provide negligible loadings of suspended solids). 

Also in 2008, a TMDL was established for White Oak Bayou concerning nutrients and low dissolved oxygen.  This is primarily due to the watershed being dominantly cropland, and reductions in nonpoint sources are essential in meeting the desired waterbody conditions.  

The outfalls should have no adverse effect on water quality due to the discharges consisting of only noncontact wastewater and storm water.  

V.	TYPE OF WASTEWATER TREATMENT:

None.

VI.	EPA APPLICABLE CATEGORICAL GUIDELINES

40 CFR Part 455 Subpart C Pesticide Chemical Formulating and Packaging Subcategory, which states there shall be no discharge of process wastewater pollutants.

VII.	DATA FROM APPLICATION FORMS 2E & 2F

	Outfall 003:
Parameter	Maximum Daily Value	
BOD5	<5.0 mg/L	
TSS	48.0 mg/L	
Oil & Grease	<1.7 mg/L	
COD	39.8 mg/L	
pH (Range)	6.1—8.96 S.U.	
Total Nitrogen	1.2 mg/L	
Total Phosphorus	0.603 mg/L	
Arsenic 	0.201 mg/L	
Total Kjeldahl Nitrogen (TKN)	1.02 mg/L	

	Outfall 004:
Parameter	Maximum Daily Value	
BOD5	<16.0 mg/L	
TSS	18.0 mg/L	
Oil & Grease	<1.7 mg/L	
COD	20.7 mg/L	
pH (Range)	6.06 -8.19 S.U.	
Total Nitrogen	7.22 mg/L	
Total Phosphorus	0.65 mg/L	
Arsenic 	0.412 mg/L	
Total Kjeldahl Nitrogen (TKN)	6.6 mg/L	

VIII. 	WATER QUALITY LIMITATIONS BASED ON WASTELOAD ALLOCATION 

	N/A

IX.	CATEGORICAL GUIDELINE LIMITATIONS CALCULATIONS

N/A

X.	PROPOSED FINAL LIMITATIONS 

1.	Average Permit Limitations

Outfall	Parameter	Categorical Limitation	Water Quality Limitation	Present Permit Limitation	Proposed Permit Limitation	Basis1	
MS0037621-003	Flow	--	--	Report	Report	ENJ	
	pH	--	6.0—9.0 S.U.	6.0—9.0 S.U.	6.0—9.0 S.U.	WQS	
	COD	--	--	Report	Report	ENJ	
	Arsenic	--	--	Report	Report	ABS	
MS0037621-004	Flow	--	--	Report	Report	ENJ	
	pH	--	6.0—9.0 S.U.	6.0—9.0 S.U.	6.0—9.0 S.U.	WQS	
	COD	--	--	Report	Report	ENJ	
	Arsenic	--	--	Report	Report	ABS	

2.	Maximum Permit Limitations

Outfall	Parameter	Categorical Limitation	Water Quality Limitation	Present Permit Limitation	Proposed Permit Limitation	Basis1	
MS0037621-003	Flow	--	--	Report	Report	ENJ	
	pH	--	6.0—9.0 S.U.	6.0—9.0 S.U.	6.0—9.0 S.U.	WQS	
	COD	--	--	Report	Report	ENJ	
	Arsenic	--	--	0.36 mg/L	0.36 mg/L	ABS	
MS0037621-004	Flow	--	--	Report	Report	ENJ	
	pH	--	6.0—9.0 S.U.	6.0—9.0 S.U.	6.0—9.0 S.U.	WQS	
	COD	--	--	Report	Report	ENJ	
	Arsenic	--	--	0.36 mg/L	0.36 mg/L	ABS	
1ENJ = engineering judgment; WQS = water quality standard; ABS = antibacksliding

Outfall 001 – This is the non-contact cooling water outfall, which is no longer functioning or attached to any process that could discharge cooling water. As a result, this outfall has been removed from the proposed permit. 

Outfall 003 and 004—All parameters are monitored quarterly and reported annually.  Flow is estimated.  COD, pH, and total arsenic are monitored using grab sampling.  Grab samples must be taken in the first 30 minutes (or soon thereafter as practicable) of the storm event.  All samples should be taken from any storm event that is greater than 0.1 inches and at least 72 hours from the previously measurable (greater than 0.1-inch rainfall) storm event.  The permittee shall also record the following: date and duration (in hours) of storm events; rainfall measurement/estimate (in inches) of storm event that generates run off; duration between sampled storm event and previously measurable storm event (greater than 0.1-inch rainfall); and an estimate of the total discharge (gallons) for the event.