Managing Hazardous Waste

We strengthen regulations and streamline waste management

Investment Waste Produced in Jewelry Manufacturing Fact Sheet

January 2002*

What is this Waste?

Investment molds are used to cast pieces of jewelry. The plaster material (investment) used to form the mold contains gypsum and silica. After the the investment has been used to cast a piece of jewelry, it is broken apart to remove the jewelry in a process called devestment, and the used investment becomes waste. Devesting of jewelry castings can generate metal dust and silica dust.

Why is this Waste Hazardous?

Investment waste may be hazardous if it contains silica dust or metallic “fine powders1” that are harmful to human health and the environment2.

Why Must this Waste be Managed Safely?

If your investment waste is hazardous to human health and the environment, it is important that you manage it safely, even if it contains precious metals. Current laws and regulations tell you how to manage hazardous waste in order to protect public health and safety, and the environment3. These laws and regulations also specify how to recover precious metals from hazardous wastes that contain precious metals. Jewelry manufacturers can protect public health and safety, and avoid costly fines and penalties, by managing their hazardous wastes in compliance with these laws and regulations.

How Should I Manage this Waste?

If your business generates a hazardous waste, it is your responsibility to ensure that you manage this waste properly (please see the DTSC fact sheet on “Hazardous Waste Generator Requirements for Jewelry Mart Operators“). The recovery of precious metals from hazardous investment waste is considered hazardous waste treatment4 and requires a permit or grant of authorization.

It is unlawful to dump any hazardous waste into the trash or onto the land, or to pour hazardous waste down the sink, into a storm drain, or down the toilet. If you want to treat any hazardous waste that you generate, or if you want to recover precious metals from your hazardous investment waste, you must get a permit or grant of authorization for onsite5 hazardous waste treatment. You can contact your local Certified Unified Program Agency (CUPA) for assistance, or DTSC at 1 (800) 728-6942 if there is no CUPA in your area.

Can I Send my Investment Mold Waste to a Company that can Recover Precious Metals from the Waste?

Yes. However, if your investment waste is hazardous waste because it contains metallic “fine powders,” toxic silica dust, or any other material that is harmful to human health or the environment, it can only be sent offsite6 to a facility that is permitted to treat the waste. It is unlawful to use the United States Postal Service, any common parcel carrier, or anyone other than a DTSC-registered transporter to transport your hazardous waste offsite. For additional information regarding transport requirements, please see the DTSC fact sheet on “Hazardous Waste Generator Requirements for Jewelry Mart Operators.”

More Information & Contacts

For more information and questions, please direct them to our Regulatory Assistance Officers using the information below. If calling from outside California, please call the “Outside CA” telephone number provided:

Toll-Free in CA: 800-728-6942 or 800 72-TOXIC
Outside CA: 916-324-2439

For assistance or additional information, please contact the DTSC Office nearest you. For a list of all offices, go to our Office Address and Phone Numbers web page.


1“Fine powder” is a metal in dry, solid form having a particle size smaller than 100 micrometers (0.004 inches) in diameter. (Cal. Code of Regs., tit. 22, § 66260.10.)

2Cal. Code .Regs., tit. 22, div. 4.5, ch. 11.

3Health & Saf. Code, div 20, ch 6.5, and Cal. Code .Regs., tit. 22, div. 4.5.

4“Treatment” is any method, technique, or process designed to change the physical, chemical, or biological character or composition of any hazardous waste or any material contained therein, or removes or reduces its harmful properties or characteristics for any purpose, including, but not limited to, energy recovery, material recovery, or reduction in volume. (Health & Saf. Code, § 25123.5 and Cal. Code Regs., tit. 22, § 66260.10.)

5The term “onsite facility” is summarized for purposes of this fact sheet to mean a hazardous waste facility at which hazardous waste is generated, and which is owned by, leased to, or under the control of the generator of the waste. (Health and Saf. Code, § 25117.12 and Cal. Code Regs., tit.22, § 66260.10.)

6An “offsite facility” means a hazardous waste facility that is not an onsite facility. (Health & Saf. Code, § 25117.11 and Cal. Code Regs., tit. 22, § 66260.10.)


This fact sheet does not replace or supersede relevant statutes and regulations. The information contained in this fact sheet is based upon the statutes and regulations in effect as of the date of the fact sheet. Interested parties should keep apprised of subsequent changes to relevant statutes and regulations.