The posting
Plant Manager – Liquid Manufacturing
Department: Operations
Location: Onawa, Iowa
Reports To: Liquid Operations Manager
FLSA Status: Exempt (Salaried)
Employment Type: Full Time
Direct Reports: Up to 15 employees (production, blending/filling, and maintenance staff)
About us
Since 1983, Horizon Ag-Products has led the emerging biostimulant industry, manufacturing soluble humus products that support plant and soil health. Based in Lakewood, Colorado, we employ about 135 people across six manufacturing plants and several surface mines nationwide, and we are proud to make the best products in our industry. We build trusted, lasting relationships with growers through science-driven solutions, and we hold ourselves to values of integrity, stewardship, innovation, respect, and accountability. We work hard, look out for one another, and stay true to the mission and values outlined at www.horizonag.com.
Position Summary
Horizon Ag is seeking an experienced Plant Manager to lead our liquid manufacturing facility in Onawa, Iowa. Reporting to the Liquid Operations Manager, the Plant Manager holds full site-level accountability for safety, environmental compliance, quality, production, cost, reliability, and people – running the facility as a business rather than simply a production line. The role covers the full liquid manufacturing process, from raw material receipt and blending through filling, packaging, and shipment, and leads a team of up to 15 employees. The successful candidate will build a plant that performs reliably and predictably, meeting or exceeding safety, quality, delivery, and financial targets through disciplined daily management and strong, hands-on leadership.
Essential Duties & Responsibilities
The Plant Manager performs the following duties personally or through subordinate supervisors, including but not limited to:
Safety, Environmental & Quality
• Enforce all Environmental, Health, Safety, Security and Quality (EHSSQ) programs and build a culture where safe execution is non-negotiable, targeting zero serious incidents through active management of leading indicators (near misses, critical-control effectiveness).
• Operate the site continuously within all environmental permits (emissions, waste, water, process discharge), anticipating risk to achieve zero preventable violations.
• Own manufacturing quality outcomes rather than delegating them to the Quality function – specifications, process capability, deviations, and customer-impacting defects – driving a right-first-time culture that eliminates chronic defects.
• Ensure safe handling, storage, and containment of bulk liquid raw materials and finished product (tanks, totes, drums, bulk tankers), including spill prevention and secondary containment integrity.
Production & Operational Performance
• Deliver ≥95–98% schedule attainment (where inputs and demand support it) by managing day-to-day production operations, true plant capacity, and constraint utilization across blending, mixing, and filling.
• Manage OEE as an economic loss-management tool and treat yield/material loss as lost money, quantifying and closing out every significant loss.
• Maintain accurate, well-rotated inventory of raw materials and finished goods to prevent downtime without overstocking.
• Convert demand into a credible operating plan (S&OP), surfacing capacity, staffing, and material risks before they become missed commitments.
Financial & Cost Management
• Own plant COGS, gross margin, and conversion cost; explain material variances and drive corrective action, with no unexplained surprises against budget.
• Manage material usage and the cost of poor quality (scrap, rework, downgrade, disposal) as financial levers, reducing COPQ year over year.
• Design staffing to business requirements rather than historical headcount; review and approve payroll and overtime with the plant management team.
• Own capital projects as shareholder investment – scope, business case, schedule, and budget – and confirm promised ROI materializes after startup.
Maintenance & Reliability
• Manage plant maintenance responsibilities to ensure predictive and preventive maintenance, along with emergency repairs, are performed effectively; maintain the CMMS (e.g., Maintenance Connection) in the absence of the Assistant Plant Manager.
• Build a reliable plant rather than accepting firefighting by addressing critical equipment failure modes and driving toward a predominantly planned-maintenance environment.
• Manage energy and utilities as a controllable production input, actively reducing intensity and cost.
People Leadership & Development
• Recruit, train, and develop direct reports and frontline supervisors to deliver consistent performance across shifts, with plant performance that doesn't depend on any one individual, including the Plant Manager, being present.
• Coach, counsel, and, when necessary, discipline employees; set clear expectations and hold the team accountable to goals.
• Identify high and low performers, close skill gaps, and build succession coverage for critical roles.
Continuous Improvement, Planning & Risk Management
• Maintain a quantified pipeline of structural improvement opportunities tied to annualized savings and COGS reduction, leading root-cause problem solving that permanently eliminates systemic issues.
• Maintain enough technical depth in liquid blending, mixing, and filling operations to credibly challenge Engineering, Maintenance, and Operations on equipment limitations and constraints.
• Identify operational risks (equipment, people, materials, compliance, supply) before they become failures and maintain credible contingency plans; partner cross-functionally with Quality, Supply Chain, Regulatory, and Commercial teams.
• Translate company strategy into a 1–3 year plant roadmap covering future capacity, cost, technology, and people needs.
• Other duties may be assigned as directed by the Liquid Operations Manager.
Supervisory Responsibilities
Directly supervises up to 7 employees across production, blending/filling, and maintenance functions, and coordinates closely with the Assistant Plant Manager on scheduling, ERP/data administration, and supervisory paperwork. Responsibilities include interviewing, hiring, and training employees; planning, assigning, and directing work; appraising performance; rewarding and disciplining employees; and addressing complaints and resolving problems, in accordance with the organization's policies and applicable law.
Key Performance Indicators
• Safety & Environmental — Zero serious incidents (TRIR, severity, near misses); zero preventable environmental violations.
• Quality — First-pass yield, deviations, cost of poor quality (COPQ), and customer complaints – chronic defects eliminated.
• Production & Reliability — Schedule attainment, OEE, capacity utilization, MTBF, and planned-maintenance percentage.
• Financial — Plant COGS, gross margin, conversion cost, budget variance, and material usage variance.
• People — Turnover, engagement, internal promotions, and succession coverage for critical roles.
• Continuous Improvement — Annualized savings and structural year-over-year COGS reduction.
Qualifications
Required
• Bachelor's degree preferred (Engineering, Chemistry, Operations Management, or related field); equivalent experience considered.
• At least 7 years of experience successfully leading a team, ideally in a regulated or process manufacturing environment.
• Experience in a liquid manufacturing, blending, or process industry environment (agricultural inputs, chemicals, or related) strongly preferred.
• Strong mechanical/process aptitude and working knowledge of cost accounting concepts (COGS, gross margin, conversion cost, variance analysis).
• Intermediate-to-advanced proficiency in Microsoft Office (Outlook, Word, Excel); ERP experience (Acumatica or similar) preferred.
• Ability to manage multiple tasks simultaneously in a constantly changing environment with minimal direct supervision.
• Exceptional verbal and written communication skills, including presenting ideas, proposals, and results to management and customers.
Preferred
• LEAN or Six Sigma background and training.
• Experience with preventive/predictive maintenance programs and CMMS systems (e.g., Maintenance Connection).
• Understanding of capital expenditures, business case development, and ROI tracking.
Physical Demands & Work Environment
• Regularly required to stand, walk, and move throughout the production floor for extended periods.
• Occasionally required to lift and/or move up to 50 pounds.
• Exposure to moving mechanical parts, chemical/raw-material handling, and varying temperature and noise levels typical of a liquid blending and filling environment.
• Required to wear personal protective equipment (PPE) as designated by site safety policy.
• Some travel between company facilities may be required.
Compensation & Benefits
Compensation: Commensurate with experience. Horizon Ag Products offers a comprehensive benefits package including medical/dental/vision, 401(k), and paid time off benefits.
Horizon Ag Products is an Equal Opportunity Employer.
Horizon Ag Products will not sponsor applicants for work visas for this position.
