General Description

Common compounds of concern in degreasing fluids are:

• Methylene chloride,
• Perchloroethylene,
• Trichloroethylene,
• 1,1,1-trichloroethane,
• Carbon tetrachloride, and
• Chloroform.

Summary of Federal Requirements

Air Emissions

Unit types that are federally regulated are:

• Solvent-cleaning Machine - any device or piece of equipment that uses halogenated HAP solvent liquid or vapor to remove soils from the surface of materials. Types of solvent-cleaning machines include, but are not limited to, batch vapor, in-line vapor, in-line cold, and batch cold solvent-cleaning machines. Buckets, pails, and beakers with capacities of 7.6 L (2 gal) or less are not considered solvent-cleaning machines:
  • Batch Cleaning Machine - a solvent-cleaning machine in which individual parts or a set of parts move through the entire cleaning cycle before new parts are introduced into the solvent-cleaning machine. An open top vapor-cleaning machine is a type of batch cleaning machine. A solvent-cleaning machine, such as a ferris wheel or a cross rod degreaser, that cleans multiple batch loads simultaneously and are manually loaded are batch cleaning machine;
  • Cold Cleaning Machines - any device or piece of equipment that contains and/or uses liquid solvent, into which parts are placed to remove soils from the surface of the parts or to dry the parts. Cleaning machines that contain and use heated, nonboiling, solvent to clean the parts are classified as cold cleaning machine;
  • Immersion Cold Cleaning Machine - a cold cleaning machine in which the parts are immersed in the solvent when being cleaned. A remote reservoir cold cleaning machine that is also an immersion cold cleaning machine is considered an immersion cold cleaning machine;
  • Remote Reservoir Cold Cleaning Machine - any device in which liquid solvent is pumped to a sink- like work area that drains solvent back into an enclosed container while parts are being cleaned, allowing no solvent to pool in the work area (40 CFR 63.461).

• Vapor-cleaning machine - a batch or in-line solvent-cleaning machine that boils liquid solvent generating solvent vapor that is used as a part of the cleaning or drying cycle
  • Open Top Vapor-cleaning machine - a batch solvent-cleaning machine that has its upper surface open to the air and boils solvents to create solvent vapor used to clean and/or dry parts

• Continuous Web Cleaning Machine - a solvent-cleaning machine in which parts such as film, coils, wire, and metal strips are cleaned at speeds typically in excess of 11 feet per minute. Parts are generally uncoiled, cleaned such that the same part is simultaneously entering and exiting the solvent application area of the solvent-cleaning machine, and then recoiled or cut. For the purposes of this subpart, all continuous web cleaning machines are considered to be a subset of in-line solvent-cleaning machines;

• In-Line Cleaning Machine or Continuous Cleaning Machine - a solvent-cleaning machine that uses an automated parts handling system, typically a conveyor, to automatically provide a continuous supply of parts to be cleaned. These units are fully enclosed except for the conveyor inlet and exit portals. In-line cleaning machines can be either cold or vapor-cleaning machines.

• Remote Reservoir Continuous Web Cleaning Machine - a continuous web cleaning machine in which there is no exposed solvent sump. In these units, the solvent is pumped from an enclosed chamber and is typically applied to the continuous web part through a nozzle or series of nozzles. The solvent then drains from the part and is collected and recycled through the sump, allowing no solvent to pool in the work or cleaning area.

The most commonly found type of degreasers in federal facilities are Cold Cleaning Machines and Immersion Cold Cleaning Machine. A "new" solvent-cleaning machine is any solvent-cleaning machine the construction or reconstruction of which is commenced after 29 November 1993.

Federal regulations only apply to each individual batch vapor, in-line vapor, in-line cold, and batch cold solvent-cleaning machine that uses any solvent containing methylene chloride, perchloroethylene, trichloroethylene, 1,1,1-trichloroethane, carbon tetrachloride, or chloroform or any combination of these halogenated HAP solvents, in total concentration greater than 5 percent by weight, as a cleaning and/or drying agent. Wipe cleaning activities, such as using a rag containing halogenated solvent or a spray cleaner containing halogenated solvent are not included.

Operators of a new solvent-cleaning machine are required to submit an initial notification to the Administrator.

Immersion batch cold solvent-cleaning machines must either have a tightly fitting cover is used that is closed at all times except during parts entry and removal, and a water layer with a minimum thickness of 2.5 cm (1 in.) on the surface of the solvent within the cleaning machine; or a tightly fitting cover is used that is closed at all times except during part entry and removal and there is a freeboard ratio of 0.75 or greater.

Requirements concerning the freeboard to be maintained, collection of waste solvent, items which can and cannot be cleaned are detailed in the federal regulations.

Hazardous Materials

Depending on the type and amount of degreaser stored and/or used at the facility, EPA reporting requirements may apply. The regulatory impacts of hazardous materials being stored and/or used at facilities are outlined in the Laboratories -> Hazardous Materials Storage section of the Facility Regulatory Tour.

Summary of State Requirements

State-by-state guidance concerning air emissions can be found at ENVCAP's Air Pollution State Resource Locator.

States often require that instructions for the operation of degreaser be posted.

Laws and Statutes

The Clean Air Act