WASHINGTON — An investigation by New Zealand’s Ministry of Consumer Affairs found that 97 of the 99 apparel and textile items tested contained either no formaldehyde or very little of the chemical, which can cause rashes and, in extreme cases, cancer. Two items had more than the acceptable 100 parts per million, but a simple washing solved the problem. The government said tests by a consumer watchdog television show that previously turned up unsafe levels of the chemical were not conducted properly.