How to Dispose of Aerosol Cans

The Environmental Protection Agency (EPA) believes that the management of hazardous waste aerosol cans can be best implemented through a universal waste approach where handlers operate within a streamlined management system with regulatory oversight. On December 9, 2019, the EPA finalized the rule to add Aerosol Cans to the federal list of Universal Wastes. This final rule will impact the labeling and marking, accumulation time limits, employee training, responses to releases, export requirements, and, for large quantity handlers of universal waste, notification and tracking.

What is the definition of Aerosol Can?

As of February, 2020, the EPA defines an aerosol as a non-refillable receptacle containing a gas compressed, liquefied or dissolved under pressure, the sole purpose of which is to expel a liquid, paste, or powder and fitted with a self-closing release device allowing the contents to be ejected by the gas. Because the DOT language is more inclusive than the proposed language, it better matches the intent of the proposal to apply to all types of aerosol cans, including cans that dispense product in the form of paste or powder, and would not require states that have already added aerosol cans to their universal waste program to change their regulations.

Current Regulations

On March 16, 2018 the Environmental Protection Agency (EPA) proposed adding aerosol cans to the federal universal waste list. This proposal recognized that the inclusion of this waste stream as a universal waste could better ensure that aerosol cans are managed appropriately from cradle to grave. Aerosol cans are widely used for dispensing a broad range of products including paints, solvents, pesticides, food and personal care products.

The Consumer Specialty Products Association (CSPA) estimates that 3.8 billion aerosol cans were filled in the United States in 2015 for use by commercial and industrial facilities along with households. Aerosol cans may be dangerous if mismanaged, particularly when exposed to excessive heat, which may result in increased internal pressure and eventually could cause the container to burst and release its contents. If the propellant or product is ignitable, this could result in a rapidly burning vapor “fireball.” Even if the propellant is not ignitable there are dangers from a bursting aerosol can as parts of the aerosol can could become a projectile. After the proposed rule-making was announced the EPA took public comment on the proposed standards. The docket number for this rule-making is EPA-HQ-QLEM-2017-0463.

The Environmental Protection Agency (EPA) has added hazardous waste aerosol cans to the universal waste program under the Federal Resource Conservation and Recovery Act (RCRA) regulations. The aim of this rule is to benefit the establishments generating and managing hazardous waste aerosol cans. These establishments include retail stores and others that discard hazardous waste aerosol cans. The rule will ease the regulatory burdens on these establishments and promote the collection and recycling of these cans and encourage the development of municipal and commercial programs to reduce the amount of aerosol cans from going to municipal solid waste landfills or combustors. This final ruling will impact the following areas for all handlers: Generator Status Universal Waste Aerosols do not count towards Generator Status.

Guidelines and Best Practices

The final rule requires aerosol cans to be labeled as “Universal Waste—Aerosol Can(s),” “Waste Aerosol Can(s),” or “Used Aerosol Can(s).”

  • The final rule allows for generators to store aerosol cans for up to one-year.
  • Employees must be trained on handling and how to safely puncture and drain universal waste aerosol cans – if applicable to facility.
  • Aerosol cans will now be exported as Universal Waste.
  • Notification and Tracking will only be impacted for large quantity universal waste handlers. Handlers must make a notification before beginning to puncture the aerosol cans.
  • Under the universal waste rule, a handler of universal waste can send the universal waste to another handler, where it can be consolidated into a larger shipment for transport to a destination facility.
  • Universal waste destination facilities are subject to all currently applicable requirements for hazardous waste treatment, storage, and disposal facilities (TSDFs) and must receive a RCRA permit for such activities.
  • This will make it more economical to send hazardous waste aerosol cans for recycling for recovery of metal materials. This final action is estimated to result in an annual cost savings of $5.3 million to $47.8 million.
  • The EPA is requiring leaking or damaged aerosol cans that show evidence of leakage to be packaged in a separate closed container, overpacked with absorbents or immediately punctured and drained in accordance with the aerosol can Universal waste requirements.

Gemini Disposal Services can help you disposal of your aerosol cans and/or universal waste in a safe and economic matter. If you need to dispose of your aerosol cans, request a quote and we will work with you to properly manage your universal waste.

A Guide to Grease Thickeners

Used for over 3000 years, grease is a key lubricant used to operate a variety of machines and bearings. Over 80% of the world’s bearings are lubricated with grease. Grease is an excellent lubricant to use when liquid lubricants fail to do the job. Greases are made of three main components: base oil (70-95%), thickener (3-30%), and additives (up to 10%). We are going to examine the second component: thickeners. Thickeners are essential as they are the “sponge” that holds the base oil and additives.

What are Thickeners?

When combined with the base oil and additives, the thickener forms a semi-fluid structure. Conventional thinking suggests the structure indicates the grease is mainly thickener, however, the thickener is a material that holds the lubricant until it is dispersed. As mentioned above, the overwhelming majority of any grease is composed of base oil. There are many types of compounds that can be used as thickeners.

Greases are classified into two major families: soap and non-soap thickeners. Over 90% of greases worldwide are classified as soap thickeners. Soap-based thickeners are produced via an acid-base reaction known as saponification. The end-result is a soap and water mixture. The water is removed and the remaining soap is used as a thickener for grease. The type of soap thickener will depend on which acids and bases are used in saponification. Some common compounds used are:

  • High molecular weight fatty acids: Stearic and 12 Hydroxy Stearic Acid (12 HSA)
  • Short chain complexing acids: Tallow, Azelaic, and Sebacic Acid
  • Most bases are a metallic hydroxide compound (i.e. lithium, calcium, etc.).

Types of Soap Thickeners

Simple Soap: This results from the reaction of one fatty acid and a metallic hydroxide. The most common soap, lithium soap, is produced

Types of Soap Thickeners – Source: NYE Lubricants

with 12 HSA and lithium hydroxide. The metallic hydroxide defines the thickener and other types besides lithium can be used.

Mixed Soap: Less common than simple soap, mixed soap is created in similar fashion as simple soap. However, the “mixed” characteristic is derived from mixing multiple metallic hydroxide compounds with a fatty acid. A common mixed soap is Ca/Li soap, which is made with calcium hydroxide and lithium hydroxide.

Complex Soap: Like simple soaps, complex soaps use a single metallic hydroxide. In order to create the complex-thickened grease, a fatty acid is combined with a short chain complexing acid. The acid mixture is then combined with a metallic hydroxide to for a complex thickener. Lithium complex grease, the most popular in North America, is made with lithium hydroxide, 12 HSA, and azelaic acid. These thickener types have an advantage over simple soap because of better high-temperature properties.

Types of Non-Soap Thickeners

Urea: Also known as polyurea, these thickeners are a reaction product of di-isocyanate combined with mono and/or diamines. The ratios of the ingredients will determine the characteristics of the thickener. This classification includes diurea, tetraurea, urea-urethane and others. Since there are no metallic elements in polyurea grease, the grease is ashless and subsequently more oxidatively stable. Polyurea greases are the most popular non-soap grease today.

Organophilic Clay: Also referred to as organo clay or clay thickeners, these thickeners are mineral based usually made from bentonite, hectorite, or montmorillonite. The minerals are purified into a clay and treated to be compatible with organic chemicals. The clay is dispersed in a lubricant to form a grease. Clay greases have no melting point and are traditionally used in high-temperate greases (however the oil will oxidize quickly at elevated temperatures).

Other: Polyurea and clay thickeners are the most used non-soap greases, but there are some other specialty thickeners that are used. These include:

  • Teflon
  • Mica and silica gel
  • Calcium sulfonate
  • Polytetrafluoroethylene (PTFE)
  • Carbon blacks
NLGI Grades – Source: Noria

NLGI Classifications

In addition to composition, the other key classification for grease is quite obvious: thickness. Defined as consistency, a grease’s consistency is its resistance to deformation by applied force. This is measured by penetration. A standard test, specifically ASTM D217, measures cone penetration after five (5) seconds for a grease at 77 F (25 C). The unit of measure is tenths of a millimeter and the NLGI classifies grease based on its penetration. The range of grades is 000 to 6. See the chart to the left for a full breakdown NLGI grades.

Most greases today fall in between the 1 and 3 grades with NLGI 2 being the most common. High penetration greases such as 00 and 0 can be used in central systems and colder environments.

Selecting the Appropriate Thickener and Grade

The right grease could vary greatly depending on your application, operating environment, and other factors. High temperature environments may require firmer (higher NLGI grade) greases and certain thickeners with high-temperature properties. It is best to consult OEM guides or speak with your grease manufacturer or distributor to get a recommendation.

Switching and mixing greases could either prove to be extremely costly. Most thickeners do not mix together and there are specific greases that are not compatible with others. It is recommended to match “like-for-like.” If you plan to make a switch, it is best to completely drain your equipment before applying new grease.