Board of Public Works
Aerosol containers offer the consumer a wide variety of products in a very convenient and easy to use package. Their convenience has lead to rapid expansion of the aerosol container market, which in turn has raised concern over the disposal of these containers. This fact sheet investigates ways for businesses to reduce or eliminate the problems associated with disposal of aerosol containers.
According to the latest annual survey conducted by the Chemical Specialties Manufacturers Association, an estimated 2.9 billion aerosol cans were fined in 1988, a sharp increase over 1987 production. On a per capita basis, 12 aerosol containers are filled annually for every man, woman, and child in the United States.
1 billion aerosol spray cans filled with personal care products were manufactured in 1988. 650 million cans of household products, 440 million cans of automotive and industrial products, 331 million spray paints and finishes, 190 million insect sprays, 157 million food products, 8 million animal care products (e.g., flea sprays), and 31 million miscellaneous products were also manufactured in 1988.
Products can be dispensed in a number of forms such as wet sprays (insecticides, oils and paints), fine sprays (toiletries and personal items), powder sprays (antiperspirants), foams (shaving creams,whipped creamed cleaners), or pastes (food items). Products are packed into containers as solutions, emulsions, or powders.
Propellants provide the driving force for ejecting the product. Both liquefied and compressed gases are used as propellants. An advantage of liquid propellants over compressed gas is that the driving force or pressure inside the container remains constant over time. This provides a consistent delivery of the product.
Common liquefied propellants include hydrocarbons such as highly flammable propane, butane, or isobutane, and to a decreasing extent, chlorofluorocarbons (CFCs). In most cases, various combinations of propellants are used to achieve the best economy, pressure, anca safety.
Production of aerosol containers declined to a lower 2.1 billion units in 1982, following the controversy over CFC emissions and depletion of the ozone layer. In the early seventies, seventy-five percent of the CFCs produced were used as propellants in aerosol sprays. More recently, the percentage has dropped to less than 13 percent.
Board of Public Works
REV. I
City Hall
200 N. Spring Street Room 353
Los Angeles, California 90012
(213) 237-1209
Compressed gas propellants such as carbon dioxide, nitrous oxide, nitrogen, or air have seen increased use in the effort to replace CFCs. This change has required alteration of products and containers, at considerable cost to the industry. A disadvantage of compressed gas is the drop in vapor pressure that occurs as the contents are depleted, causing changes in the delivery rate of the spray.
In the past, most steel aerosol containers were tin plated and soldered with tin-lead alloys containing some antimony and silver. These hazardous metals are being eliminated from many can manufacturing operations through the use of mass production welding. The switch to welding eliminates the need for soldering and hence the need for tinplate. In lieu of tinplate, an internal coating of epoxy resin is used to protect the contents of the container from contamination.
In a word, the answer seems to be: usually. According to existing regulations, both the content and the container are hazardous. Empty cans with residual amounts of propane, butane and other hydrocarbons are hazardous by virtue of their flammable contents.
Cans that contained only food products or other non-harmful substances must also be treated as hazardous waste, because they meet the criterion of reactivity. The residual pressure in them can cause the container to explode if exposed to heat or punctured.
Unfortunately, the only way to rinse out most cans, and to relieve the residual pressure they contain, is to puncture them. This happens to violate the safety precautions on most cans, and is prohibited by the Federal Insecticide, Fungicide, and Rodenticide Act. Rapid pressure release can be dangerous under some circumstances, and can add to air emissions. Also, you will generate rinse water which may be difficult to dispose of if it contains hazardous substances.
While existing laws say the spent aerosol containers are hazardous waste, the California Department of Health Services (DHS) has issued a number of exemptions. Farmers, for instance, can throw their emptied pesticide containers in the trash if they triple rinse them first and properly manage or recycle the rinsate. This does not violate because pesticide cans can be opened without puncturing. Many pesticide containers can also be recycled.
Aerosol cans in household wastes are not treated as hazardous at the present time. This exemption applies to empty containers that did or did not contain hazardous wastes. Such containers must be completely emptied (to the extent practical under normal use) and disposed of at the point of use and not accumulated over time.
The reason against accumulating household aerosol containers is mostly due to safety concerns for the households, trash collectors, landfill operators, and fire fighters (in the event of a landfill fire). Stockpiling of empty aerosol containers (that did or did not contain hazardous wastes previously) poses a greater risk in the event of a fire or explosion than well dispersed single unit containers. Since the quantity of containers generated by households within a short period of time is relatively small, the risk or extent of an explosion is limited.
DHS has granted still another exemption to a school district to dispose of empty aerosol paint containers in the trash, provided it is done, it the point of use and not accumulated over time. If your shop falls under the definition of a small quantity generator, you might consider applying to DHS for an exemption. According (To the Code of Federal Regulations, a small quantity generator is one who generates less than 100 kilograms of hazardous waste in a calendar month. Unless an exemption is received, however, aerosol cans must be treated as hazardous to be in compliance with the law.
DHS and Los Angeles County Department of Sanitation indicate that spent aerosol containers must be regulated as hazardous and transported to facilities for disposal in the appropriate manner. Household, while exempt, should dispose of such containers at household hazardous waste roundups. Businesses are required to hire a contractor to dispose of aerosol containers in an appropriate manner. To be in full compliance with the law, these containers must be accompanied by a manifest and an EPA ID number. Aerosol containers that do not contain hazardous wastes are treated in the same way as containers that do contain hazardous wastes.
A pragmatic approach to final disposal of empty containers, and one that might be developed in the future, would be to puncture the containers in special facilities that can execute such jobs in a safe and appropriate manner. The punctured containers could then be appropriately treated (triple rinsed in the case of containers that held hazardous materials) before being landfilled as non-hazardous waste. Control of residual vapors and rinsate would be required for such an operation. Such operations would still have to comply with the disposal requirements of the appropriate Regional Water Quality City Control Board and Local County Agencies.
An approach applicable to City of Los Angeles shops, or to other government agency shops as well, is to organize "milk runs" in which aerosol containers from all of the agency's shops are collected and consolidated. They could then be disposed of in one shipment, under one manifest. This would have to be done every 3 months or more often, so that storage limit requirements are not exceeded.
No matter which approach is ultimately implemented for managing aerosol can wastes, it makes very good sense to reduce the quantity of waste generated as much as possible.
Waste minimization measures aimed at reducing the amount of waste generated through the use of aerosol containers fall into two basic approaches:
Most items which are available in aerosol containers are also available in non-aerosol form. Aerosol containers offer convenience to the consumer by providing a product in readily usable form. A food product such as whipped cream provides a good example. Anyone can buy whipping cream, vanilla, and sugar and mix up a bowl of whipped cream. But it's faster to buy a can at the store. The major point to remember is that most purchases of aerosol products are done for convenience and not necessity.
Another example is the use of roach sprays. People prefer the convenience of aerosols because they are quick and effective. Unfortunately, most insects quickly develop resistance to these sprays. This leads to ever increasing dosages and the need for newer and stronger formulations each year. Few would consider the time honored method of mixing boric acid with cacao powder and sprinkling this powder around. While boric acid is an effective insecticide to which insects do not develop tolerance, its action is slow and its application messy.
For products which must be applied in a spray form (as an example, hair spray), alternatives to aerosol containers are available. Concerns over VOC emissions associated with the propellants used in hair spray lead to the development and acceptance of the hand pump spray unit. Hand pump spray units offer several advantages over aerosol containers in addition to the elimination of propellant emissions. Most hand pump containers can be refilled and reused.
This is a benefit even when the manufacturer does not provide the product in bulk form for refilling. When an aerosol nozzle clogs, the container and its contents must be discarded. When a hand pump unit breaks, the contents can be saved and later transferred to another hand pump dispenser.
For situations where the use of aerosol containers cannot be avoided, proper material management practices are essential to reducing the amount of waste generated. While many of the following measures and aimed at large-scale industrial or institutional users of aerosol products, most small-scale users can implement these measures as well.
The first step in insuring that most, if not all of the aerosol container contents can be fully used is to follow the instructions shown on the label. It is important to hold spray cans upright so as not to needlessly vent propellant and depressurize the container before it is empty. When dealing with sticky materials such as paint, which can dry and clog the can, the nozzle should be cleaned after each use. This can be performed by turning the can upside down and spraying a short blast of propellant through the nozzle.
When ordering aerosol products, try to select those which contain the least hazardous or environmentally detrimental materials. For example, purchase aerosol products that use nitrogen as the propellant instead of hydrocarbons.
Proper storage facilities should be provided for all materials and products. Storage facilities should be designed to keep products free of dirt, moist, excessive heat and cold, and exposure to sunlight. These practices increase the useful shelf-life of a product and the ability to utilize all that the can contains. Improper storage can also lead to product labels being damaged or lost. If a product cannot be identified, then it has to be disposed of as waste.
When aerosol containers are not in use, their protective caps should be replaced. Replacement of the cap helps avoid contamination and rusting of the container top. Other benefits include ease of container identification, ability to stack containers and minimize storage space, and reduced likelihood of nozzle damage. When a nozzle is damaged, the aerosol container must often be discarded. Nozzle damage can also result in uncontrolled venting of the contents, which can be dangerous to anyone in the immediate area, and can present a fire danger if contents are flammable.
Order products according to need. Purchasing agents often purchase products in bulk because of pricing incentives. If these products cannot be used, they must instead be disposed of as waste. The cost associated with hazardous waste disposal will often exceed the purchase price of the item. When this happens, any savings realized at the time of purchase are lost. A proper material purchasing program should be fully aware of and account for potential disposal costs before making any purchase.
A coordinated material purchasing program can also help a shop to reduce waste. A coordinated program can monitor all requests for products throughout the company or plant, and implement proper purchasing policies. These policies should include staggered deliveries, standardization of products purchased, inventory checks to avoid over-purchase, and screening of products for hazardous components.
In addition to the coordinated material purchasing program, an inventory control program which can trace chemical usage from cradle to grave is essential. An inventory control program can promote sharing of materials between common users, provide data on who is using extremely hazardous products, identify who are the large volume users, locate where unused caches of materials are, and delineate where waste reduction/material substitution options are viable. Inventory control programs should be designed to rotate stock on a first-in, first-out basis.
Staggered deliveries minimize the amount of stock on hand at any given time. This reduces the potential for a product becoming waste because its shelf-life expired while in storage. Standardization reduces the number of products purchased, and thus decreases the different types of wastes which must eventually be managed.
A good material purchasing program should encourage product suppliers to become responsible partners in a waste minimization program. Such suppliers should be able to provide quick delivery of small orders, accept the return of unopened stock, and be willing to offer or assist in the location of off-site waste management outlets for their products.
A refillable valve is an adaptation allowing smaller containers to be refilled from a larger, more economical container which may not be capable of spraying. One of the problems with this type of system is the ????? transfer rate through the small orifices once the pressure has nearly equalized in the two containers, and the large amount of propellant that may eventually be lost during these transfers.
The most effective ways of reducing aerosol container waste is to avoid purchasing products in aerosol form. When this is not feasible, then maximize usage of all aerosol materials. Implement coordinated and well focused material purchasing and inventory control programs if possible. These programs can help in avoiding the purchase of aerosol products that contain hazardous materials and in reducing the amount of left-over/out-dated materials that end up as waste.
Some additional publications available from the Hazardous and Toxic Materials Project that may be helpful are:
Technical Assistance for this publication provided by Jacobs Engineering Group
City of Los Angeles
Board of Public Works
Hazardous and Toxic Materials Project
200 N. Spring Street, Room 353
Los Angeles, California 90012
Further Information
For further information and assistance or to request additional publications please contact the HTM Project at:
City of Los Angeles
Board of Public Works
Hazardous and Toxic Materials Project
200 N. Spring Street, Room 353
Los Angeles, California 90012
(213) 237-1209
The Board of Public Works Hazardous and Toxic Materials Project was established by the Los Angeles city council in 1988. The purpose of this program is to demonstrate the national policy of minimizing hazardous waste generation and ensure the compliance with hazardous materials and waste requirements. Technical is provided to City agencies and through on-site consultation, information minimalation and waste assessments.
Last Updated: November 13, 1995