United States National Risk Management

Environmental Protection Research Laboratory

Agency Cincinnati, OH 45268

Research and Development EPA/600/SR-01/001 January 2001

Project Summary

The report summarizes available information on candles and incense as

potential sources of indoor air pollution.

It covers market information and a review of the scientific literature. The

market information collected focuses

on production and sales data, typical

uses in the U.S., and data on the sources

and quantities of imported products. The

estimated total sales of candles in 1999

varied between $968 million and $2.3

billion, while imports were $486 million.

The U.S. imports and exports of incense

in 1999 were $12.4 and 4.6 million, respectively. The scientific literature review gathered information regarding the

emission of various contaminants generated when burning candles and incense, as well as the potential health

effects associated with exposure to

these contaminants. Burning candles

and incense can be sources of particulate matter. Burning candles with leadcore wicks may result in indoor air

concentration of lead above EPA-recommended thresholds. Exposure to incense smoke has been linked with

several illnesses, and certain brands of

incense also contain chemicals suspected of causing skin irritation.

This Project Summary was developed

by the National Risk Management Research Laboratory’s Air Pollution Prevention and Control Division, Research

Triangle Park, NC, to announce key findings of the research project that is fully

documented in a separate report of the

same title (see Project Report ordering

information at back).

Candles and Incense as Potential

Sources of Indoor Air Pollution:

Market Analysis and Literature

Review

Lynn Knight, Arlene Levin, and Catherine Mendenhall

Background and Approach

The potential indoor air impacts of burning candles and incense have drawn increased attention in recent years. There

are three particular areas of concern.

Candles with lead-core wicks have been

found on the market and have been

shown to be a source of airborne lead

when burned. Metal cores are used to

stiffen wicks so they will not fall over and

extinguish themselves as the surrounding wax melts. Lead was commonly used

as a core material until 1974 when the

U.S. candle manufacturing industry voluntarily agreed to discontinue use of lead

in wicks. However, candles with lead

wicks have been found on the market by

an academic as well as a consumer protection group study. Most of the candles

found that contained lead wicks were imported.

Secondly, under imperfect combustion

conditions, candles emit soot and can

cause property damage by blackening

walls, ceilings, and carpets. There have

been an increasing number of complaints

regarding black soot deposition in homes

in the last decade. Candles are one

source of soot. With candles, sooting occurs as a result of incomplete combustion. Candle composition, wick length, and

drafty conditions can all affect candle combustion. The amount of soot produced

can vary greatly depending on the type of

candle. One type of candle can produce

as much as 100 times more soot than

another.

Thirdly, incense smoke can be a major

source of particulate emissions in indoor
2

air. The particulates produced when burning incense can deposit in the respiratory

tract. These emissions may contain contaminants that can cause a variety of

health effects, including mutagenic effects

and airborne dermatitis.

EPA is currently testing emissions from

candles and incense to generate data.

To support this effort, the report collects

and presents two types of data: (1) market information, and (2) literature on the

potential impacts of burning candles and

incense on indoor air quality.

The market information collected focuses on production and sales data, typical uses in the U.S., and data on the

sources and quantities of imported products. In addition, the report summarizes

the results of a scientific literature review.

It reports the findings in the scientific literature regarding the emission rates of

the various contaminants generated when

burning candles and incense, as well as

the potential health effects associated with

exposure to these contaminants.

Market Information

Publicly available sources of data,

mostly from the U.S. Bureau of the Census, as well as private market studies

and trade literature were consulted to produce this summary of economic information regarding the candle and incense

markets. Dialog Information Service and

Internet searches were performed to identify market and related information. The

U.S. Bureau of Census was contacted to

obtain import and export data. The National Candle Association was contacted

to obtain industry data.

The Census Bureau reports 107 manufacturing establishments; however, industry estimates range from 160 to over 200

manufacturers. Many manufacturers are

very small. Candle sales have been growing rapidly in the last 10 years (10 to 15

% per year), fueled by consumer interest

in aromatherapy and increased demand

for home fragrance products in general.

There is a wide range in estimates of

candle sales in the U.S. The Census Bureau reports a total value of shipments in

1997 of $968 million; industry estimates

put 1999 sales at $1.3 billion just for

scented candles, and up to $2.3 billion

for all candles. The majority of candle

imports are from China. A large portion of

imports come from Hong Kong, Mexico,

and Canada as well.

There are no public data on incense

manufacturers; private data show at least

26 manufacturers. Limited discussions

with industry representatives indicate that

there are probably many more very small

incense manufacturers. The majority of

incense imports are from India, China,

and Thailand.

Potential Indoor Air Quality

Impacts

Scientific literature, consumer interest

group reports, and trade and industry studies were consulted for this summary. Resources were identified through Medline,

Toxline, a database of on-line journals,

the National Candle Association, and extensive web searches. The studies were

diverse in origin; many of the incense

studies were performed in Asia, where

incense is commonly burned.

Candles

According to the literature reviewed,

burning candles containing lead-core

wicks can result in indoor air concentrations of lead above EPA-recommended

thresholds. All three of the scientific studies, found analyzing indoor air concentrations resulting from burning candles

with lead-core wicks, indicated that this

indoor air threshold was exceeded. Regarding candles with non-lead metal

cores, the literature did not indicate that

wicks made with zinc and tin emitted these

metals at concentrations that would raise

health concerns when burned indoors.

In addition to lead, consumers are exposed to concentrations of organic chemicals, such as formaldehyde, acetaldehyde,

and acrolein. One study showed worstcase scenario candle emissions containing levels of these three chemicals that

exceeded EPA-recommended thresholds.

Other studies indicated no health hazards.

Sooting can occur when combustion

conditions are impaired when burning

candles. Scented candles are more likely

to produce soot than unscented candles.

Sooting can cause property damage by

blackening surfaces. Although soot particles are very small and can potentially

penetrate the deepest areas of the lungs,

studies regarding potential human health

effects associated with soot from candles

were not found in the literature search.

Incense

Large quantities of particulate matter

are generated when burning incense.

Studies that examined the emissions of

specific contaminants from incense smoke

indicated that benzene and carbon monoxide may be emitted at concentrations

that could pose human health risks. Several studies indicated links between exposure to incense smoke and health

effects, such as cancer, asthma, and contact dermatitis. Some studies indicated

possible mutagenic and genotoxic effects.
United States

Environmental Protection Agency

Center for Environmental Research Information

Cincinnati, OH 45268

PRESORTED STANDARD

POSTAGE & FEES PAID

EPA

PERMIT No. G-35

Official Business

Penalty for Private Use

$300

EPA/600/SR-01/001

L. Knight, A. Levin, and C. Mendenhall are with Eastern Research Group, Lexington, MA

02421-3136.

Zhishi Guo is the EPA Project Officer (see below).

The complete report, entitled “Candles and Incense as Potential Sources of Indoor Air

Pollution: Market Analysis and Literature Review,” (Order No. PB2001-103 924; Cost:

$27.00, subject to change) will be available only from

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

Telephone: (703) 605-6000 (world wide)

 (800) 553-6847 (U.S. only)

The EPA Project Officer can be contacted at

Air Pollution Prevention and Control Division

National Risk Management Research Laboratory

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711-0001