A Social Security trust fund was established by Congress. It was established by an "Act of Congress"and included in the federal statutes generally known as the United States Code.
For organizational purposes, the federal statutes or US code is divided into "titles". The Social Security Act is included in Title 42 which deals with the public health and welfare.
Title 42 is broken down into chapters. The chapters include categories such as child nutrition, public works or facilities, sanitation and quarantine, Social Security, etc. Social Security is listed as chapter 7
Chapter 7 is further broken down into subchapters. Subchapter II deals with Federal Old Age, Survivors, and Disability Insurance Benefits. ( Chapter XVI deals with Supplemental Security Income for aged, blind, and disabled. This will be discussed in another section of this website.)
Subchapter II has a number of sections dealing with payroll taxes, quarters of coverage, benefits for veterans, disability determinations, etc. Under this subchapter, workers and employers each pay a Social Security or "F. I. C. A." tax of 6.2% of the workers earnings. Of the 6.2% tax, 5.3% is earmarked for the Social Security Retirement and Survivors Trust Fund and 0.9% is designated for the Disability Insurance Trust Fund.
Currently the Social Security Trust Fund has receipts of about $115 billion and makes payments of about $145 billion, representing a deficit of about $30 billion. in 2015, the trust fund would not have had enough money to pay disabled workers the full amount promised had not Congress passed a special law to borrow money from the retirement trust fund.
To qualify for disability insurance benefits, a person must be "insured". To be insured, a person generally must have worked and paid Social Security taxes at least 20 out of the past 40 quarters prior to becoming disabled. Each year is divided into 4 quarters. To earn a quarter of coverage, a person must have earned a threshold of income for a particular year. Each year that amount is adjusted for inflation. The maximum number of quarters a person can earn in one year is 4.
The rules are slightly different for persons 30 years of age and under. Those persons must have worked at least 50% of the quarters between age 22 and the date they became disabled. However, a minimum of 6 quarters must have been earned to be insured.
To be deemed disabled, a person must be "unable to engage in any substantial gainful activity by reason of any medically determinable physical or mental impairment which can be expected to result in death or which has lasted or is expected to last for continuous period of at least 12 months" The impairment or combination of impairments must be of such severity that the applicant is not only unable to do his or her previous work, but cannot, considering his or her age, education, and work experience, engage in any other kind of substantial gainful work, which exists in the national economy.