Lead is also used in ceramic glazes and as a stabilizer in plastics. Lead was used extensively as a corrosion inhibitor and pigment in paints but concerns over its toxicity led to the CPSC in 1977 to ban the use of lead in paint for residential and public buildings.
The first digit assigned to all Visa cards is four, and the second through sixth numbers are connected to the financial institution. Then, either the seventh through 12th numbers, or the seventh through 15th, are the account number, while that final 13th or 16th digit is the check number.
For example, the MasterCard system is identified by the number 5, American Express and Diners Club credit card numbers start with the number 3, while Visa and Discover Card systems are identified by the numbers 4 and 6, respectively. Each credit card number has a structure that varies by system. In the MasterCard system, digits two through six are used to identify the bank number, digits seven through 15 designate the account number and digit 16 represents a check digit.