ESCONDIDO -- On Friday morning, Escondido firefighters delayed entering the burning North County Plating shop on Industrial Avenue because of concerns about hazardous materials.

Their concern makes sense. Environmental regulators have long seen metal plating as one of the most sensitive businesses around, and metal platers routinely use strong acids, cyanide and heavy metals such as chromium and cadmium in their work.

The county's Hazardous Materials division took air samples as well as samples of the runoff created by the water used to fight the fire Friday, and determined that there was no immediate danger to people nearby, said division chief Michael Dorsey.

"We're pretty confident that there is no environmental damage," he said. "The Fire Department let the fire burn itself out, so there was less liquid runoff than there could have been."

While extinguishing the blaze Friday morning, firefighters set up dams to contain possibly contaminated water. They noticed that a puddle of liquid corroded the fittings on their hoses while the hoses were in the puddle, Escondido Fire Department spokeswoman Carol Rea said.

The liquid will be disposed of at a hazardous waste facility outside the county, officials said.

North County Plating on Industrial Avenue specialized in decorative plating for cars and motorcycles and has been featured in motorcycle enthusiasts' magazines.

North County Plating was run by siblings Alicia and Mario Moreno, who inherited the business from their father. Alicia Moreno is a leader of North County's Association of Latino Merchants.

The Morenos could not be reached for comment Friday.

Plating is the process of putting a coat of metal, such as chrome, gold, tin or nickel, on an item to make it shiny or protect it from rusting. Platers dip the items into vats of acids and metal solutions and use electrical current to deposit the metal on the target.

Both to ensure the safety of construction workers on the site and to assess any environmental damage, authorities will now need to determine if hazardous materials have seeped into the ground or permeated the structure. Dorsey said initial test results could be available in a week.

A small amount of runoff entered the storm drain, but county officials tested the runoff's acidity and determined that it wouldn't be harmful.

Some plating businesses have switches that allow the storm drain to be blocked in case of a spill, but it's not clear whether North County Plating had one.

Cleaning up after the fire could be expensive.

Last year, the federal Environmental Protection Agency had to supervise the cleanup of another Escondido plating business near Westside Park.

Vats of caustic acids and cyanide solutions had been left unattended and rain had created an "Olympic-sized swimming pool" after the business was evicted from its building. The EPA later hit the founder's son with a $600,000 bill.

Rising costs associated with stricter environmental regulations are driving some plating shops out of business or out of the United States. San Diego County has a third fewer than it did six years ago, according to the county Department of Environmental Health.

"I wanted to get some car parts done and it seemed like I might have to go to Mexico to do it," said John Robertus, executive director of the San Diego Water Quality Control Board.

He said the water quality board would take action, such as issuing a cleanup order, if the contaminated water reached Escondido Creek.

Plating shops may be more dangerous to people who work there every day than to people who have to come in once or twice.

Safety regulators closely watch the use of hexavalent chromium, which several medical studies have shown causes cancer when inhaled. Some plating businesses don't work with chrome because of the extra health risk.

In February, the federal Occupational Safety and Health Administration tightened the standard for exposure on the job to hexavalent chromium by tenfold after being sued by a chemical workers union in the 1990s.

The standards are anticipated to require plating shops to buy expensive "fume scrubbing" equipment that removes chromium from the air.

Contact staff writer Quinn Eastman at (760) 740-5412 or qeastman@nctimes.com.