A manager at Sameer Agriculture and Livestock Limited was arrested on Tuesday on accusations of flouting Nema's regulations for discharging effluent.
Satendra Sharma is the plant manager for Daima dairy company, whose products are processed by Sameer.
Mr Sharma was arrested in Molo by police and inspectors from the National Environment Management Authority.
He was apprehended at the company's officers in Salgaa along Nakuru-Eldoret highway as the inspectors carried out a crackdown on users of banned plastic bags. The manager was taken to Molo Police Station.
Betty Nzioka, the authority's monitoring and evaluation director, said an update would follow.