Private equity firm Gryphon Investors acquired Trinity Consultants, a Dallas-based provider of environmental services and staffing. Terms of the transaction were not announced.

Trinity’s offerings include air quality permitting and compliance services, which aim to help its clients comply with federal, state and local air quality regulation. In addition, its On Demand Environmental business unit provides staffing of environment, health and safety personnel.

Trinity has more than 300 employees in 33 offices.

Gryphon’s portfolio also currently includes legal staffing provider Update Legal, according to its website. In addition, a former Gryphon portfolio company is healthcare staffing firm Medfinders, which was sold to AMN Healthcare Inc. (NYSE: AHS) in 2010.