Hidden hazards

Chemistry lesson one: Accidents happen, like the recent spill at Exeter High School in New Hampshire, when fumes in a lab class sent three students to the hospital and shut down the school for the day.

Chemistry lesson two: Adding unknowns to the mix -- like improper storage and handling of toxic substances -- can be a formula for disaster.

In January, firefighters responding to an alarm triggered by a chemistry experiment at Pope John XXIII High School in Everett found a jar containing a potentially volatile material that is used to produce rocket fuel. Deemed unstable, the chemical -- 2, 4-dinitrophenol -- was detonated by the State Police Bomb Squad.

Chemicals that were 20 years old were found during a cleanup at Everett High School. At Lynnfield High, 30-year-old species were discovered, preserved in large amounts of formaldehyde. Chemicals dating to the Depression were found at Swampscott High School.

While schools have long been aware of the dangers of working with chemicals such as 2, 4-dinitrophenol and mercury, these incidents show how easy it is to lose track of laboratory materials, sometimes decades old, according to area science teachers. Past practices, such as ordering chemical substances in bulk and keeping them in separate storage closets, fostered a system that sometimes allowed schools to become unwitting harborers of hidden hazards.

''I'm surprised that a high school would have this type of compound within a lab setting, but it's not unusual," Phillip Retallick, senior vice president for Clean Harbors Environmental Services, said of the Pope John incident. ''School labs tend to accumulate a large amount of compounds."

Old substances in science labs often aren't found until teachers do major cleanups, such as after the departure of a longtime teacher, or when school supplies have to be moved. Compounding the problem is a lack of guidelines from the state Department of Education instructing public schools on how to store and dispose of chemicals and how often to take inventory, according to science teachers.

When chemicals are stored in school laboratories longer than they should, it is often because teachers have never had proper lab safety training, or because ''they knew about it and they didn't want to deal with it," said Jim Kaufman, president of the Laboratory Safety Institute in Natick. The institute is a 30-year-old nonprofit organization that teaches courses on laboratory safety to teachers, organizations, and companies.

''Many times people say it costs too much to implement a lab-safety procedure," Kaufman said. ''Our response is that there are many, many things you can do that can make a difference that don't have to cost a penny. Good practice says that you walk around, that you look around and you have a look at what you're storing. It strikes me as odd that it can take 30 years [before a school lab is cleaned out], that their colleague was a pack rat and they didn't know."

Pope John vice principal Mary Anne DiMarco said administrators discovered the chemical jar in November and alerted a Clean Harbors official, who told them it was a high-hazard explosive that was more than 10 years old. The school arranged for Clean Harbors to dispose of it while the students were off for February break, DiMarco said. She said Clean Harbors told her it was stored safely, as long as it wasn't tampered with. But after firefighters spotted it in January, they immediately arranged a controlled explosion at Revere Beach.

The evacuation at Exeter High on March 30 was the result of a small spill that occurred during a ''relatively routine experiment," said Gary Heald, the school's principal. A class of 18 juniors was attempting to produce oxygen from bleach using cobalt chloride, but two students used too much, causing a bubbling reaction in the beaker that spilled a bit of the substance and released fumes, Heald said.

Storage problems have become more evident as safety awareness increases. A cleanup of Everett High School's chemical lab several years ago produced substances that were more than 20 years old, said Superintendent Frederick Foresteire.

''We had quite a bit of material that had been there for quite some time," Foresteire said. ''Any chemical left there had become hazardous."

At the end of every school year in June, Foresteire said, inventory is taken of the chemical substances and a private company is hired to dispose of any hazardous materials. Such disposal can be expensive -- Pope John was going to pay Clean Harbors $2,700 to dispose of the single jar -- which has prompted many schools to be more proactive in tracking chemicals stored in labs.

State education departments do not provide safety procedures that science teachers can consult, but a study by the state Department of Public Health recommends guidelines for inspecting science labs. Science department heads said they also rely on safety pointers from manufacturers, such as Illinois-based Flinn Scientific Inc., which sells about 1,000 chemicals to schools across the country, including many north of Boston.

''We now know so much more about how certain chemicals and substances can harm us, just breathing them, much more than we did in the '60s and '70s," said Mark Meszaros, vice president of technical services at Flinn Scientific.

''Mercury and heavy metals are not used in schools as much anymore; unfortunately [in] schools built in the '20s and '30s, which in Boston you have a lot of, people had these chemicals, but they went away and left them there. It's like food. When they age, they can either become less hazardous or more hazardous."

Meszaros said many schools are turning to ''microscale science," a method in which lesser amounts of chemicals are used in school experiments. Students can still see the results of the experiment when using 2, 3, or 5 milliliters, he said, but ''you don't have 100 milliliters of stuff to evaporate or dispose of."

Swampscott High School is one of those practicing microscale science, said director of science curriculum Bernard A. Kravitz.

Instead of paying to dispose of unused or old materials, Kravitz said the teachers order such small amounts that they use them up by the end of the school year. Smaller amounts of chemicals are also safer for students to handle, he said.

''Some schools still have people who are cavalier with their agents and do large demonstrations," Kravitz said. ''I don't know that I want to test my school's insurance policy."

Kravitz said the school has been moved to three different town buildings and is preparing to move again. After one of those moves, he said, science teachers found chemical bottles dating back to the 1930s.

''We found all sorts of old stuff," Kravitz said. ''The reason it can pile up in a school is that it's very expensive to dispose of it. You can't throw it down the drain."

Lynnfield Science Department chairwoman Jessica Lisiak said a cleanup of the lab during construction also produced the discovery of ''amphibians, reptiles, salamanders, some mammals, and guinea pigs" that were more than 30 years old and preserved in large amounts of formaldehyde, a substance that most school labs now keep to a minimum.

Lisiak said that ordering a large number of specimens for dissection is no longer the norm at the school because the focus of biology has evolved to biochemistry and the study of genetics. Most dissections have been replaced by simulated computer programs, Lisiak said.

''Now chemicals there are only about a couple of years old. Our stuff is relatively new," Lisiak said. She added that the school's lab is now equipped with more safety materials, such as cabinets for flammable materials and chemical spill buckets.

Science department heads said effective education requires schools to keep potentially hazardous substances on hand despite the risks. Also, labs are the only places where students will learn about the hazards of chemicals, many of which can be found in their homes, teachers said.

Kaufman, head of the Laboratory Safety Institute, said his organization does not support banning any substance from laboratories, as long as they are handled properly.

''One of the most carcinogenic items, aflatoxin, occurs naturally in peanuts and corn," Kaufman said. ''We're concerned that people are trying to create an artificially safe environment, where carcinogens don't exist. Paint thinner, nail polish, as adults, we know how to handle these chemicals. . . . We see science classes and well-informed science teachers who emphasize safety, then the child learns that it's OK to care about health and safety."

Or, as Kravitz put it, ''You can't dance around good science because of the chemicals."

Katheleen Conti can be reached at kconti@globe.com