How dangerous are fragrances in cleaning products?

The soap scum is building up in the shower stall. Time to get out the cleaner. You spritz it and, ah, that nice lemony scent.

But what's it doing to your nasal passages, to your skin?

Environmental and health advocates have long been concerned about cleaning products. The multitude of chemicals that have replaced good old elbow grease make the job easier, but with potential side effects to human health.

Fragrance chemicals in particular have been a focus of the advocacy group Women's Voices for the Earth, which contends they can irritate sensitive skin, cause breathing problems and coughing, and have neurotoxins that can affect the immune system.

The International Fragrance Association of North America would differ. Spokeswoman Elena Solovyov said that the industry has rigorous standards and review processes and that products with them can be used safely.

But Women's Voices for the Earth notes that more than 3,000 chemicals are used in fragrance formulations. It has had a long-running campaign, bolstered by lawsuits, to get manufacturers to reveal — and list on labels — what ingredients are used.

The group also would like to see wider use of safer chemicals, so they welcome the expansion of a U.S. Environmental Protection Agency program encouraging that.

They include Clorox Commercial Solutions Green Works All Purpose Cleaner Spray; Earth Choice BioLaundry Advanced Enzyme Detergent; and cleaners from Earth Friendly Products, such as Creamy Cleanser and Parsley Plus.

The program also publishes lists of safer chemical ingredients, and in July it added fragrance chemicals to that list — 119 of them for starters, with more in the wings.

The idea is that this makes it easier for manufacturers to develop safer formulations, and to move them more easily through the DfE process.

Manufacturers voluntarily submit chemicals, and third-party "profilers" evaluate them. Two profilers have been qualified by the EPA, but it's the manufacturer that pays them.

What was notable about the 119 fragrance chemicals on the list was that only four got the highest clearance — a green light. Most got the designation of a yellow triangle, which often indicates a potential sensitization problem.

Solovyov, of the International Fragrance Association of North America, defended the industry's review processes.

"Ironically," she added, proponents of DfE labels "often ask our perfumers to work with natural essential oils and extracts, but because of the complexity of their makeup and potential to cause sensitization in some people, many naturals cannot clear DfE criteria or can only clear it with restrictions."

But she said the DfE list "will provide a real benefit" for companies aiming to devise safer formulas.

Most are eager to do so, said Pamela Dalton, a researcher with the Monell Chemical Senses Center in Philadelphia.

Some fragrances used over the years "have been shown to have high sensitization potential," she said.