ARB Orders Tough Rules for Airborne Chromium Emission

The state Air Resources Board on Thursday directed air pollution control districts throughout the state to adopt tough new controls on emissions of cancer-causing hexavalent chromium from metal-plating operations.

Chromium emissions under the order would be cut by at least 97% over the next four years and prevent between 210 and 2,600 cancer cases in California during the next 70 years, the board said.

The rule, approved on a 7-0 vote during a meeting in Los Angeles, marked the second time in six months that the board has required controls on emissions of air toxics not because they contribute to smog but because they cause cancer.

Last year, the board ordered additional controls on benzene vapors from gasoline sold at service stations in relatively smog-free rural areas where vapor recovery systems had not been previously required. Benzene is a carcinogen. Chromium was first identified by the state as an air toxic two years ago.

‘High-Risk Compound’

“It’s a very high-risk compound we’re dealing with,” ARB executive officer Jim Boyd told the board.

The chromium controls, to be implemented within six months, would have their greatest impact in the four-county South Coast Air Basin where 273 of the state’s 416 chrome-plating businesses are located. The basin includes Los Angeles, Orange, Riverside and San Bernardino counties.

Hexavalent chromium is widely used in business and industry. Lead chromate, for example, is the pigment in yellow paint used to mark traffic lanes. In water solution, hexavalent chromium is converted through electroplating to the bright metallic chromium coating seen on such products as shower heads, car bumpers and engine parts.

Carried by Mist

Airborne chromium is carried by the mist produced during the reaction between chromate plating material and the electric current used to apply it.

It is estimated that there are 12,200 pounds of uncontrolled emissions from chrome-plating and chromic acid anodizing operations annually in the state, 65% of them in the South Coast Air Basin. Anodizing, like chrome plating, is done in a bath of hexavalent chromium solution, and causes hexavalent chromium emissions. It creates a wear- and corrosion-resistant surface on the object anodized, but does not result in a metallic chromium layer.

Under the order, known as an “airborne toxic control measure,” chrome plating and chromic acid anodizing operations would have to reduce emissions between 95% and 99.8% within six months to four years. The degree of controls and the length of time allowed to achieve them would depend upon the size of the individual business and the amount of its emissions. Larger businesses with more emissions would have to meet the most stringent requirement. The rule would be modified only if a demonstration project proves within the next 18 months that controls cannot achieve a 99.8% emission reduction.

If the control costs were passed along to customers, the present $200-per-square-foot price of plating would increase from 18 cents to $15 a square foot, the board said. The annual cost of the control equipment would run from $4,500 for a small shop and $18,000 for a medium-sized shop to $150,000 for a large operation, ARB staff member Cliff Popejoy said.

However, representatives of Metal Finishing Assn. of Southern California testified that the costs would run two to three times higher than the state estimates.

Expressed Concern

“The association is very concerned the proposed regulation will put some of our members out of business,” association attorney B. J. Kirwan told the board.

While 21 million Californians are exposed to various amounts of the toxic material, the ARB said the heaviest concentrations are near chrome-plating businesses, a contention supported by a citizens committee that has won a years-long battle to close down a chrome-plating operation near Shull Elementary School in San Dimas.

Jeff Schenkel of the San Dimas Concerned Citizens Committee urged the board to require all chrome-plating and chromic acid anodizing operators to comply with the strict 99% emission controls, not just the smaller firms.